I think Comcast cares about the Flyers, that's part of the problem! If the Roberts family didn't want to still own it or it wasn't viewed as integral to the corporate history why still own the team? I think it's also theoretically possible to change things without changing ownership. I would have said - and likely did say - everything you just said about the Flyers about Middleton as recently as two years ago. But he's evolved some, and also got kind of lucky (IMO) with Dombrowski.
Of course he's also not a corporation. In theory if Comcast was willing and able to clean house (Scott, Holmgren, Clarke) there could be real change. Truth is in the Phillies' case that really didn't begin to happen until the institutional old guard either died or retired.
Actually it's worse than that isn't it? All of those things have cratered and can only be fixed by winning. But for Comcast the Flyers are just part of a much bigger media and arena/events business. As long as that's still working for the board and shareholders (and/or they keep the team because the Roberts family wants to keep the team) the team won't be sold. It's hard for me to say what benefit the team really provides as just a speck in the overall media landscape, but it must still provide onoe.
I reckon the Sixers arena isn't really going to happen but that might be the only thing that I could see changing everything, if losing basketball (including Nova and NCAA tournament) and having to compete with concerts prompts them to get out (with a new owner who's happy to work with/be a tenant to the Sixers).
For now, the best we can hope for is what it also looked like the Phillies might have to do for a while (and would have if MLB's salary cap and free agency worked like the NHL's) - conceded that they completely botched the 2014-2018 rebuild and do it all over again.