Nowadays? In terms of tech its all spread too thin, this isn't the 80s or the 90s. For modern challenges i'd say the greatest milestones are set by the devs who can best figure out good business models and adequate production pipelines, for being bad at that is whats stopping bigger, better and larger games from being made.
To that end, studios like From, Larian, Epic Games, Atlus, Capcom, as well as smaller ones like SCS software, Ghost Ship Studios and New Blood Interactive, have all shown how to best cultivate audiences and nurture them, which eventually led - or will lead - to the creation of some pretty amazing stuff that wouldn't be possible with just budget and talent.
And even if you try and argue i'm wrong, the results speaks for themselves. These are all studios who managed to extract great success stories from what most considered (until they came around) niche and unpopular types of games, often unique enough that they're considered the ones who created or pioneered a genre.