From things you've written, you are in the same age group as many of the ditto-heads and you go online. Older users can and do email and web surf and access new media content that interests them, just as you do. In assuming they don't, you are making the same kind of assumption about 50 plus consumers that people here say advertisers do in deciding not to advertise in certain radio formats.
I am in a similar age of many of Rush's ditto heads except that in a few months I'll be among the 60 plus group. Yes, I do use the computer to go online for various things that are FREE. I don't subscribe to any thing, other than my high speed internet connection and the bottom of the line no frills cable service for my TV. Remember, we baby boomers grew up in a world of antenna TV and radio, in other words FREE radio and TV. Granted most people today do have cable TV as the picture is better than the old antenna, besides it's no longer any "fun" to go up on the roof to fix a broken wire on the antenna, so for that reason alone, I have cable. I don't watch that much TV and frankly there isn't enough on there on a regular basis I'd choose to watch so it's just not worth the additional cost. I have an MP3 that I down load some of my CD's and some free things from sites that offer free downloads of their programming, such as the Lutheran Hour podcasts, Methodist Thinker podcasts, and NPR podcasts, all free. I've not looked for music to download for free as that seems to be a minefield and I've read where folks have had hassles, so why bother.
Many TV shows, movies, etc, are available on YouTube, Hulu, and Fancast ( for comcast customers). However, Glenn Beck's, is not available, yet many of the Fox programs are, so that implies that Beck has chosen to charge to view his shows online. You can get a clip of Beck's TV show on the Fox web site, but to see the entire show, you've got to pay. Thankfully for me, I'm not that interested in what he says so Fox and Beck don't make any money from me. The networks offer their TV shows on line AFTER they've aired on TV for free with spots, just as Hulu and Fancast do. NPR and PBS also offer their shows online AFTER they've aired on radio or TV for free with their corporate underwriting messages included usually at the beginning of the program.
As much as elRusbo is on the radio, 6 days a week for three hours each day totally 18 hours a week essentially saying the same thing each week I'm frankly amazed that anyone would pay to hear him, same with Beck. Talk about over exposure.
I've not subscribed to XM radio, more because of the up front cost of buying a rather expensive radio that isn't portable so you can take it from car to house, meaning you'd need two expensive radios if you wanted to listen at home too, probably an additional cost in the monthly fee too. My guess is, that most people who do subscribe to XM is because they bought a new car that already had the XM radio installed and got hooked on it for the free year you typically get when buying a new car. Then it's just a matter of paying the monthly charge. I did get to experience XM while on vacation this past summer, in the rental car we had. It was fine, once we found a station we liked as there are quite a few (the rental car doesn't provide a list of stations so you're just station hopping trying to get past the rap and crap to find what my wife and I liked. But having said that, once we found a couple of stations we did like, we did enjoy it, but not enough to go and buy an expensive radio, then pay to get it installed in the car. So maybe when I buy my next car, it will have XM already there, and then I'll give it a try for the free year and then decide if it's worth the monthly fee.
I know others my age, who also do not subscribe to XM/Sirus radio, or pay to see or listen to things online. Now, some of them, who are really into sports will have a sports package with their cable TV subscription as they live to watch their favorite sports teams, sometimes from other cities, play. Granted, I'm sure there are boomer ditto heads out there who spend the money to watch the dittocam and re-listen to what Rush says for a fee. I've just not run in to any.
The other large part of Rush and Beck's audience is the "Greatest Generation", the 70 - 80+ crowd, who really love AM radio and will use their computers to forward those annoying email stories that are never true. The 70+ folks I know, do not use the computer for anything else and frankly are afraid of the computer. They have enough trouble working their high tech TV's that no longer just have a few knobs to turn, DVD players, VCR's, and CD players and just do not go online to watch or listen to stuff and will not pay to do that online. Many of these geezers have dialup as it's the cheapest so viewing stuff really isn't an option for them online.
My point was, Sterns audience is younger and more likely to be willing to fork over the cash to first get his show on XM, and then to pay for the other extras he may be offering. Rush's audience will be less likely. Granted some will, MY GUESS is, most won't.