Is this a question from a pure theoretical point of view?

If a soft-limit exists, you would have to ask internally.

Technically nothing would prevent a very large number of physical tables, even if most of the time the ID attribute (which isn't supposed to be used anymore as the UID is the official unique identifier but both still exists all the time) is a 5 digits number.

So the limit could be 100'000, or maybe it's a signed 32bit int and the limit could be 2 billions and something.

Practically, if you get any close to a possible limit, the issue is somewhere else : are you really doing things in the right way?