The King’s Gambit was a top Grand Master opening for hundreds of years. It’s rarely played in serious tournaments anymore.
I still open with the King’s Gambit now and then even though I know full well it’s almost completely busted. My results are still pretty good because I play a few tricky lines and I play aggressively against opponents who are less studied. I’m sure Fridrich will be in the tournament mix for a long time.
Ah, but it's different in Chess. Chess is a competitive sport - you're directly competing against someone else, and your skill is measured by how well you do against others. Since you are responding to your opponent's moves, if you know they are likely to do something before you actually play against them, you can prepare for it. So with the King's Gambit, top players used it for centuries because it was so hard to defend against - but as soon as the defense became common knowledge among top players, it was no longer a good move, because you could be sure that your opponent would know how to beat you if you used it. You're in a position where your opponents sometimes don't know how to beat the King's Gambit, but if you were a grandmaster you could expect your opponents to always know it, so instead of being a good move it would be extremely dangerous.
Apparently Street Fighter (and other competitive fighting games) work in a similar way, although on a much faster timescale. If someone discovers a really great move or combination, it will soon be picked up by everyone because it is a reliable way to do well. But as soon as someone else finds a way to counter it, and that becomes widely known, all of the top players stop using the move. It was only good in the first place because there WAS no defense, and now that everyone can counter it there is no advantage to be gained from using it anymore. (Note that, since Street Fighter is a realtime game, expert players will sometimes use attacks that they know can be easily defended against, because by doing something unexpected they can confuse the opponent into making a mistake in a defense that they don't have practice with. Chess does not have this issue because the opponent always has plenty of time to think about the move before they have to react, so if you try to do something which is easily countered, an experienced opponent will always be able to defend against it.)
On the other hand, cubing isn't competitive in the same sense. You might think cubing is a competitive sport because you go to competitions and compete against others, but in fact all you are doing is trying to solve a particular cube as fast as you can, and the ranking of competitors against each other isn't related to that at all. There is nothing head to head against cubing, and what that means is that if someone is using a really good method there is no possible "defense" - an "opponent" in cubing can't do anything to counter your method, except by getting faster times, which still wouldn't prevent you from using the method. The only reason a cubing method would be invalidated would be if there was one that was released that was significantly better, and even if that did happen it would still be acceptable for people to stick with the old method, because you can still get acceptable times with it. I can imagine a future in which 11.xx official averages are no longer world-class, but I can't imagine one in which 11.xx would not be considered good on an objective scale.
I guess I'd compare cubing in this sense to something like competitive swimming or track. Where we have method, they have form. Since those sports are all about times and there is no direct competition (in the sense that what you do will greatly affect the opponent and vice versa), there is nothing that could invalidate a particular form except the discovery of a better one, and even then it will still be possible to be decent (although not world-class) with the old form.
