Jamie was already wrong two years ago by over 1000%. And, Cuban has already redacted his negativity and become hugely bullish on blockchain and digital currencies.
It's a matter of time before Jamie changes his perspectives. However, he's in banking so his statement is clearly rooted in a massive conflict of interest. He will need to wait until the space is a bit more regulated and he is sure that it is in Chase's best interest before he goes public with his confidence in the tech.