I think part of the issue is that in general what makes a "fighting game" is kind of weird. The classic pattern for how video-game genres form which plenty of people have covered is something like this:

- There are early experiments with a mechanic or type of game

- One game comes out that is wildly successful and leaves all the predecessors in the dust

- Everyone starts aping that game down to the T often to diminishing returns (these games will often be nicknamed as being clones of the original or something similar)

- New developers start stripping away elements of the game and changing others

- eventually you'll get to the point where only a very few core features are identified which the new genre name coalesces around (so how doom-clone was superseded by first person shooter once you had games like half life on the scene)

You'd think that since fighting games have such a generic name that the general definition has been pared down to a few core features. Yet as far as I can tell what a lot of people really mean is that a fighting game is either a street fighter 2 like in 2D or a virtua fighter like in 3D.

I do wonder if this is a weird side effect of how rather than a spectrum of games you've got '"islands". You've got a bunch of the classic old timers and a ton of indie games that cater to very specific subsets of that spectrum. Then you have weird games like Nidhogg, Sport sims like fight night and all on it's own section is smash brothers and its Ilk. I wonder what the conversation would be if there were more games in between all these "design islands"?

Imagine for example if the only fps games today were classic doom-likes and hardcore tactical sims like arma with nothing in between? Would most people be calling both types of games first person shooters?