[usrusr]

Space to put them, terrestrially, is not infinite. Demand has a hard ceiling.

[Cthulhu_]

Plenty of space still, but we're running into other scaling issues now - power grids are at their limits. And on sunny days there's a lot more supply than demand, but that can be mitigated by adding more (battery) storage.

[FeepingCreature]

That's a supply ceiling. Funnily, it's also one that's solved by putting them in space.

[DoctorOetker]

unless demand comes from space