I think you're wrong mate, and the football league maybe had a tad more vision than you. Greater attendances for a competition that never attracted decent numbers, some great away days for the fans at PL grounds and some home games that'll capture the imagination of some local fans akin to how the 3rd round FA Cup games does. TV will have more of an interest and £1m from the PL. For what it's worth I don't think the U21's will end up winning the thing, as they'll find the going tough against some of the hardened pro's of the lower leagues. It's only a trial anyway, 1 season is the deal, so we'll see how it goes and who's wrong or right.....
Capture the imagination? Dude, we're talking about academies here. They're not 'proper' teams, they have no (or at least a very small) fan base, no history, 90% of the players no-one outside of the club in question would have heard of anyway, the match is meaningless to the club in question... to them it's basically a training fixture. TV won't have much of an interest... how many academy games are on TV? Playing Wycombe Wanders, Portsmouth, Accrington Stanley or AFC Wimbledon will not suddenly make academies TV worthy especially the academies of the non-Big 4/6... no offense to any of those clubs. As for attendances, there may be a few hardcore people who go, but really who cares about seeing a bunch of kids who happen to play for Liverpool or whatever? You could argue the FA Cup sees Premier League sides playing kids but that's not a given, nor is it a requirement therefore you're more likely to see senior team players, even if not the entire 1st XI. Not to mention all the people signed up to boycott matches.
Quite a few youth games are on tv if you look in the right places. It's also u23's with three over aged players allowed so not just youth academies.
On what channels? Man U TV and Chelsea TV probably, and I know the televise the FA Youth Cup Final... what else? Yeah that's true, in theory. In practice, players aged 22-23 will either be in the first team squad or on loan, getting better experience than a few cup matches... Let's be realistic, it'll most likely be academy sides.