About 20 years ago, one of the Bay Area's secondary PBS stations (KCSM in San Mateo, if I remember correctly) experimented with commercials for about 3 minutes of each hour, before and after programming - as a funding alternative to those periodic pledge break weeks. The station was having a hard time getting enough funding, being a poor cousin to big-guns KQED in San Francisco and KTEH in San Jose.
They accepting only informational-type commercials (not hard-sell ads). I thought it was a worthy experiment, but it was abandoned. It's worth noting that since then, those PBS "major funding provided by..." announcements have become like mini-commercials.
But an hour a day block of commercials - no - nobody would watch. It's one thing to watch a half-hour infomercial about one product (and I rarely do that), but to watch an hour block of 30 second to 2 minute ads would be mind-numbing.
The idea is similar to those 7 to 8 minute commercial stop-sets you hear on music radio stations now. They allow the stations to play more sets of uninterrupted music ("12 in a row," and all that), but I don't think it serves the needs of the advertisers. Are you really listening to the 11th commercial in a 15 commercial block? I doubt it. I'm surprised the advertisers put up with it.