>>29639107>it tests how a game holds up after the initial gameplayThe problem is that it varies from person to person. One person may want to replay the game but another may have enjoyed it but not to the extent that they would want to play it again.
The only reason people cared about replayability in the past is because games were ridiculously expensive for the time now they're dirt cheap by comparison and everyone can buy them.
>but back in the day full games with high replayability where the norm.You clearly haven't experienced games back in the day. Especially since games were notoriously short but masked with difficult situations Mega Man and Castlevania are prime examples of this.
Hell, even Mario to an extent follows suit as later Bowser fights have you deal with his barrage of hammers and fire.