I think the biggest obstacle now is the dwindling relevancy of television, especially with the younger demographics that anime tends to target. That demographic is far too used to streaming services nowadays, and anime is plentiful there (even when we exclude Crunchyroll and focus on the more general streamers like Netflix).
Crunchyroll
did launch a television channel in the US last year (
LINK), but given the difference in sale between their market and ours, I can't see there being any incentive to launch one here. A client of mine at work recently started a television channel (not anime related), and it's an extremely expensive endeavour - just getting on Sky can cost tens of thousands. Back in the day, we also had AnimeCentral (2007-2008), and that only ran from 9pm-6am because it shared a broadcasting spot with PopGirl (which led to some hilarity like
Fullmetal Alchemist playing while the channel still had the PopGirl watermark).
With Adult Swim, I wish Warner Bros. could actually sort out their distribution pipeline in general. Over here, Channel 4 seems to have a deal with Adult Swim, hence why things like
My Adventures with Superman and
Uzumaki end up on their streaming service.
My Adventures with Superman was apparently later broadcast on E4, so they're probably the ones you might want to prod about a potential block returning here.