We've mined 17m of the 21m bitcoin already.
In that time bitcoin has gone up 6 million times its original value! That makes no sense at all. Even 1000x - 10000x increase would be rather absurd
Bitcoins price is WAYYYYY TOOO HIGH!!! Only 1% of the world has adopted the coin so far. It makes no sense that the first 1% to adopt (aka miners and HODLers) should get up to a 6 million times return on their money. While someone adopting today would get a one times return. That's simply not feasible. The remaining 99% of the population will not agree to deflate their own purchasing power by 6 million - they will just continue to use Fiat.
That's the biggest problem that will prevent bitcoin from scaling.
https://www.youtube.com/watch?v=F7luAHdv61kHeres a great video from Crypto Daily discussing the problems of bitcoins price