Can Bitcoin break $15k before 2021?  

If we look back at 2017, this should be the time for price to start going up.

There is no real reason why we would not see a new ATH in the next 365 days from now.

Bitcoin is more mature than ever, a way bigger market than ever, the major global economies are printing funny money fiat literally by the TRILLIONS, more than ever, and put an unlimited unbacked debt-based currency printed by the trillions, owned by a private company (USD) vs a 21 million coin supply of an open-source currency featuring 21st century technology?

This all boils down to my gut screaming:
Don't bet against bitcoin.