I don't necessarily think these findings debunk stereo's importance to listeners, though. Even dedicated audiophiles would probably order their lists this way. Why
bother caring about stereo, in other words, if (a) you're always drowning in ads, (b+c+e) the music is always the same old limited tired stuff, (d) the stupid jock talks as much as I type in some of my RD posts, (f) it's ruined by being muffled, and (g) it's ruined by noise and static. Your survey looks completely accurate with totally sensible results, but it seems to me that it actually shows that stereo is the
first concern on the list,
after you get past everything that would
ruin a listening experience, and you can start turning your mind to
aesthetics. Note for instance how insufficient dynamic range, excessive THD, audible cart wow/flutter, vinyl surface noise, and other aesthetic sensibilities (i.e. irritants rather than showstoppers) were either unreported to you or reported less often than stereo itself. To me, this shows that stereo does actually register as important to people, but that it's simply something they don't conceive of as relevant until and unless they can "get settled in," having dealt with or avoided any obstacles that would spoil/block the listening experience.
Shifting to one decade later, and from my perspective, I grew up in a time when radios were almost always called "stereos" (or "stereo systems"), as opposed to the older term, radios. Some back then would even ridiculously refer to mono radios as stereos and say that "that stereo only works in mono." And you went to stereo shops to buy those stereos -- not to electronics stores. (Heck, you went to stereo shops in the '70s, too.) And many boom boxes in the early through late 1980s had "mono / stereo / stereo wide" flip-switches, as if to emphasize how much people loved drinking up the effect of binaural sound ("more!"). Stereo was so important to ratings that Bob Orban charged extra for his 222A in 1988 by selling it separately rather than integrating it into future 8100s or his subsequent 8200. And he only created it in response to how many stations were using linear L-R amplification and blowing their feet off with the resulting hurricanes of multipath. In fact, the same audiophile mentor I mentioned in my previous post above considered mono to stereo synthesizers the bane of his existence, because they were absolutely everywhere in the 1980s as a result of Orban (and many others) selling tons of them to TV stations at the outset of BTSC, when there wasn't yet enough real stereo material coming out of Hollywood. By this last point alone, you could say stereo was so front-of-mind to even TV viewers back then that people who owned stereo TV sets wanted to hear it
faked, if they couldn't hear the real thing.
So I'm not saying you're wrong about stereo being way down on any master list of priorities. But I think that such a list unfairly dismisses stereo's importance by placing base "requirements" (to even want to listen to anything in the first place) in the same category as the things that would matter
once you're listening.
I think the move to FM would have never snowballed had C-QUAM stereo appeared on AM in 1969 and FM remained mono. FM would have become some kind of weird, high fidelity speech broadcasting service at best, and as the noise and static levels on AM became absurd by the 80s,
then you would have started seeing some movement of music to mono FM -- by virtue of it being
forced off stereo AM by the showstopper effect of static and noise. But that movement to FM would've been accompanied, guaranteed, by cries to the FCC to authorize a compatible FM stereo encoding scheme, and fast.
During the brief period where lots of AM and FM stations were both in stereo, I think the reason the average person chose FM stereo over AM stereo was simply ... why drink a flat soda when you can drink a fresh one.
But wait.

To ordinary people with no technical knowledge of the mechanics of stereo, terms like "better," "clearer," and "brighter" would be precisely the ones they might use to describe their perception of the stereo image. Stereo is more pleasing in the general sense, so right there, that makes it "better." And "clearer" would be a valid description for how it makes different instruments more distinguishable (some are "over here," while others are "over there," leading to less crowding, and hence more "clarity" in each location). Even the word "brighter" could be attributed to those listeners' mental tracking of the stereo image, in the sense that mono sometimes cancels higher frequencies (imperfectly aligned carts or phase problems somewhere in the station/from your distributor). "Brighter" could also be how some individuals might describe stereo in so far as their minds being better able to pick out the harmonic overtones of individual instruments when those instruments were less buried in each other's ways.
Heck, audiophiles have difficulty putting the acoustic characteristics of flaws they perceive into words. How many audiophile forum threads have you seen filled with people bickering at each other, because everyone has a different way of describing the same exotic defect they're all hearing in a recording? I think this principle can be applied with ordinary people too, only in their cases, they can have difficulties conceptualizing and articulating the simple and basic things people like ourselves can instantly wrap our minds around and apply universally agreed terms to.
I can think of one interesting way to figure out how important stereo is to average people. Hand out earbuds to a focus group, with the earbuds' plug ends rigged into a Y configuration ending in two separate 3.5mm connectors. Give the group a red herring explanation for this, saying that each connector uses a different metal alloy and that after a month of listening, you want to know which they think sounds the best. (Say gold is getting too expensive, so you're trying to find some substitute that works as well as gold-tipped connectors, but that's visually identical to normal connectors.) Unbeknownst to them, one connector will internally mix L+R and give them mono in both ears. How much would you bet that by the end of the survey, everyone picked the stereo end?
Another variation would be giving people portable stereo bluetooth speakers, with a flip-switch for power that's internally rigged so when it's in the center position, the unit is off, but when it's in the left or right positions, it's on -- but in stereo only when flipped to the right. This time, just give the speakers to the group, saying it doesn't matter which way they flip the switch. Say nothing about it making a difference in the audio. Have a data-recording circuit sensor inside each speaker that records the total number of minutes, long term, that each was turned on to the left, versus to the right. You could even make sure half the speakers turned on in stereo to the left (instead of the right), and mix them up, handing the speakers out randomly, so that weird left/right psychological "biases" wouldn't even affect your results. Something tells me that when you got all the speakers back and downloaded their data for analysis, there would be a massive preference for whatever direction made each work in stereo. That people would have tried the switch both ways just out of curiosity, sensed the better sound in one direction versus the other, consciously or semi-consciously, and whether they understood that it was stereo or not, they would've preferred the stereo.