First, the news:
Chris Mack isn't the only one tweeting about this, obviously, but his was the first prominent voice I saw advocating for it. My personal feelings towards a former coach don't play into this, I just think the idea is no good. Here's why:
First, an NCAA bid accomplishes at least one of two things: it rewards the recipient for a good season (or at least a good week at the conference tournament), and/or gives them a chance to win six games and go home with the hardware.
This is obviously not the case if everyone is in. What exactly "all-inclusive" means isn't clear, but if you take it literally, well... it's everyone. Not to be mean, but for some seasons, the end is a mercy. Kennesaw State went 1-28 last year (weirdly, their one win was by 24 over Gardner Webb); was anyone begging for them to get a chance to run it to 1-29? Would their players have even wanted that?
Even if you limit it to teams at or above .500, you run into real problems. There are some really, really bad teams at that mark; scroll through KenPom if you don't believe me. You also automatically begin excluding teams that are better than teams you let in. The worst .500 team I could find was Alcorn St. at 324th in the KenPom; the worst was Washington at 54. You'd imagine there'd be some sandy pajamas if every .500 team got in and every sub-.500 team didn't.
Obviously, some of these teams have no shot at winning anything meaningful. While that's also the case in the current format, at least the bid serves as recognition of the on-court accomplishments it takes to get in rather than just surviving a season and not having too many guys test positive. You're also doling out the chance to get your brains thumped in by Kansas or someone on national TV.
This whole thing is being framed as a cynical money grab, but I'm not sure it will be effective as such. Part of what makes the tournament exciting to watch is that every win puts a team both ~17% of the way closer to the title and halfway to a meaningful landmark in the proceedings. Win two and you've got a Sweet 16 bid; I doubt anyone is going to hang a banner for their historic Sweet 128 run. It's preposterous.
That leaves the games to stand on their own merit. If you've got some sort of staggered, play-in game style setup, you're going to have a lot of games played between two objectively crappy teams with basically nothing on the line. Those don't draw great ratings when they happen in a normal season - and they happen all the time - and I don't think they'd do any better in an expanded tournament format. If it's just a straight free-for-all, you'll have to slog through a couple of rounds of what are effectively buy games before you get to good matchups. That doesn't quicken the pulse either.
If this happens, the only possible outcomes are bad. If it draws a lot of ratings, good luck getting the NCAA to go back to something more reasonable. If it doesn't, it sucks some of the remaining fun out of a season that didn't need any help being underwhelming. It's an outside the box idea in a weird season, it's just not a particularly good one.