Baseball has seen it's share f come-and-go fads. In the 1980's, the game seemed to be all about stolen bases (except in Boston). Now, even with faster players, steals are far, far less frequent.
As for bunting - well, again - it is a strategy (and not, as many suggest, a fundamental). Right no, it is a strategy no one wants to use. Maybe in 5 years, everyone will be sac bunting all the time, which will be boring as hell. But Tito stopped doing it, it worked and he won, and the league emulated him. And Bill James wrote lengthy diatribes about the importance of not wasting outs. So no one but the occasional NL pitcher does it anymore.
HR or bust is the latest fad where they practice swinging to work on launch angle and exit velocity. It's another evolutionary development. Like focusing on OBP or wRC, it won't last, since someone will come up with something new...