Bitcoin is 89% premine to any kid born today.
In 2140 it is 100% premine to any kid born that year.
Why the future generations don`t get any rewards?
What kind of design is this satoshi? to enslave the future of humanity?
Today born kids, can’t mine Bitcoins without proper equipments and big budget investment at first.
Moreover at the future the kids can earn from the blocks.
Also if there aren’t enough BTC to mine, then there should be some other valuable coin in the market available to mine.
Hope this clears your concern and doubts OP.
Let’s see what happens in the future next.