Simple analysis, yes but a very good one @culgin.

Banks are very profitable and the fractional reserve banking is key to their model. Also, many of the big banks are market makers so they are basically establishing the spread in many markets.

Using just the first part, that is why it is vital for us to get more of our holdings in cryptocurrency. Every dollar held in crypto removes $10 from the established banking system. If we just focused upon this aspect of the banks business, we would see a major impact.

Over time, I have a feeling this will be the trend. As there is more to do with crypto i.e. places to spend it, we will not see people converting it back to fiat.

This will eventually take a toll on the banks.