Let’s say you have a game and it’s optimised for maximum graphics utilisation, so you can’t do anything extra graphically. Then Unity comes along with it’s 2018.1 update and unlocks more cores/threads/processing power for your game.
What could you use that processing power for to improve your game if you cannot add anything graphically?
Physics, AI, gameplay code
Not the place for hypothetical discussions that abosolutely have no actual discussable content. There is no such thing as “optimized for maximum graphics utilization”, we don’t have species on 2018, and you haven’t provided any examples. And as @neoshaman pointed out, everything else.
There is always room to optimize, no point in “hypothetical” discussions when there are many actual, useful, actionable discussions on optimization all around the forums.