And as I said, people rarely if ever prepare openings 'dozens of moves' deep at all but the absolute top level play.
At this point you have to choose if you want chess to cater to competitive chess players (who are mostly content with the rules as they are) or amateur spectators and organizes (who want to see blood).
Ad 3. This abundance of draws (like #1) only becomes a problem at elite levels, too.
Not to mention just because a game ends with a draw doesn't mean it's a dry and boring draw. A draw can be a fascinating back-and-forth struggle full of tricks and swindles.
Same as many decisive games can actually be yawn-inducing - think 70-moves long, even endgame that comes to a conclusion only because one of the exhausted players finally blunders.
I've been watching a lot of Hikaru's streams since PogChamps put him on my radar and he is a very entertaining player IMO.
Stalemates happen less in 960.
There is some interest, and tournaments are played now and again, sure. However, it's nowhere near the popularity of classic chess, which shows no signs of "going out of style".
To provide some perspective - on lichess.org (one of the most popular sites for online chess; the one where the high-profile tournament you mentioned took place) in June there have been 70,374,749 classic games played. Chess960 accounted for 285,788 games. That's ~250 times less popular.
"Stalemates happen less in 960" - seriously? Why? Do you have any source of that claim? I could believe that draws in general are more rare (lack of opening theory makes equalizing in middle game more difficult). But why would it affect the rate of stalemates specifically?
I don't have anything against classic, and as you say, I will probably be playing it forever myself, but from a spectators point of view its more fun if there are less stalemates. There's a lot more room for errors in 960, even among GMs.
All of these attempts failed, because of several reasons:
1) The aforementioned problem of memorizing openings and accumulating draws only occurs at a very, very high level. Even if you're a GM you won't prepare at the level Carlsen et al. do, memorizing entire 30-move games they had against each other twelve years ago.
2) Opening theory moves on and playstyles evolve. AlphaZero shifted the mood from conservative, materialistic, 'computer-like' play to a highly dynamic style that puts an emphasis on piece activity. Just like when we think we got most things figured out, new breakthroughs show we've only barely scratched the surface of what the game has to offer.
3) Most chess players don't see the abundance of draws as a problem. I think it is specifically an American sentiment - in a country where you're either a winner or a loser, the game's failure to rank its top players can be frustrating.
4) Most players see preparation against their opponent as part of competitive play. Think of it as a kind of metagaming. Changing the rules would completely reset that.
5) There's a good chance that any change of rules would aggravate White's marginal first-move advantage. It doesn't matter what the computer says, what matters is how humans play it and how it reflects in the winrates among humans.
That doesn't mean the variants are bad or useless though. Bughouse and suicide chess are crazy fun