The restriction is that Bitcoin can't grow faster than total wealth forever. I.e. you can't grow total wealth by 3% and grow Bitcoin by 4% forever.

It can. The misconception that people generally have is believing that purchasing securities is a zero-sum game when in fact it's generally a positive sum game. When you buy a bitcoin (or security), the money you spent doesn't disappear so the amount of bitcoins and fiat in circulation do not change as a result of this trade. There's nothing stopping a bitcoin from being worth a million dollars or a dollar being worth a million bitcoins, it's just a function of supply and demand.