The whole genre, in some ways, has felt like some gated community to me that’s closed for anyone not willing to pour in the hours to learn.
Anyways, to me the things that make fighting games difficult and fun are what differentiate them from beat 'em ups, which get pretty boring quickly.
I don't disagree that combos are not fun to learn, but I don't know what you could replace it with. Removing it would turns games into punch, punch back, kick, kick back without any risk or counterplay. Adding blocking/countering would have to be more complicated than just "hold block" to keep it interesting and would require memorization all your opponent's moves too. I'd say Tekken 8 already has this problem especially with King's chain grabs. So lots of games are going for auto-combos to make comboing easier instead.
I actually did play Skullgirls and Street Fighter 6 in a way without learning combos for a character. It's pretty easy with a zoner, and plenty of players hate playing against that too.
But wasn't that one of the last points?
Rhythm games are fun.
Further, I dont know when you've tried picking one up last, but any title in the last few years has plenty of concern for "accessibility" especially regarding inputs.
Most competitive spaces can be described as "some gated community to me that’s closed for anyone not willing to pour in the hours to learn".
SF6 was my first fighting game. Sitting in the lab and learning to do a 3 hit combo with a dragon punch motion correctly over and over was actually rewarding. I don't think it's necessary to remove motions from the genre. I definitely would have dropped the game if my only initial choices were lab and multiplayer though.
I also enjoy rhythm games, but they're different combos. Especially for the learning process: you're really not punished for dropping combos in rhythm games, and you can keep playing as if you didn't drop it (unless you're going for the full combo of course). That's really not the case for fighting games, requiring you to restart to the beginning of the combo each time. And in a multiplayer game, it gives your opponent an opportunity each time.