In China, it mostly isn't already.

JLCPCB is so cheap because everything is standardized and automated. Their tooling analyzes your input, gives a big fat warning if it spots something it knows it can't manufacture, and renders their processing output for final approval by you. Chinese labor might be cheaper than Western labor, but it is not even remotely cheap enough to babysit every hobbyist's one-off board.

They also assume you know what you are doing. You order a board with a part rotated 180 degrees? Well, it physically fits, so they will make it like that. The final board not working as you intended is a you-problem. You put a via inside a pad and it wicks away all the solder? Not their problem. You forgot to re-render the area fills and short ground to power? Not their problem.