The competition has improved dramatically since Mortal Kombat 9, not to mention since the mid 90s. I encourage people to correct me if I am wrong, but a more accurate assessment of the early fighting game scene is that a small minority of players who spent lots of money and time in the arcades dominated while all other players were average at best. The internet did not exist so there was no access to information. You could not improve unless you wasted lots of coins.
I agree that back in the day certain fighting games required more execution (i.e., just frames, one frame links, no execution shortcuts for special moves, etc.), but the games lacked quality, particularly with respect to balance. You say you have to play "perfect" to win in Mortal Kombat 9, yet the best characters in the game ignore 85%+ of the roster. So the best players eventually master the most broken 4-5 characters regardless of execution barriers and the game becomes boring and monotonous. People, including me, quit playing Mortal Kombat 9 for this reason. Besides, fighting against 90%+ combos, infinite armor, variable frame data, several bugs and glitches, etc. is not what most people would consider "fun". Almost all of the old fighting games (i.e., 3s, MvC2, Tekken Tag 1, etc.) suffered from the same issues.