It reaches a dead end eventually. That's where we are, edge of speed, where the only mods left are aesthetics veering at photorealism.
This is also why every hard problem eventually shows up — games are just simulation + interaction, and eventually everything that can be simulated will have some attempted implementation out there, struggling along. (For some reason, this does not appear to stop at “interesting” things to simulate — see all the literal simulators on steam)