Moreover, if a marketcap is too high at the beginning, the potential growth of the investments is limited.
This is very true.
Sometimes devs can't stop their greed and it makes investors lose.
If you have a good project you will probably get tons of money but if you don't put a max cap for it, only you will win and investors won't.
That's exactly true. Cindicator is a good example for a low hard cap. It was just 15M $ I think it will increase in value very much if it is on exchanges.