Given that it's their business to make money with money, I can't see how any bank, big or small, could ignore bitcoin.
This.
Bankers don't care about the products they're investing in. They only care that those products are making money.
If gold is making money, they invest in gold. If bitcoin is making more money, they gradually move to invest in bitcoin.
There is no "bankers and the 1% love fiat money and fiat is here to stay." Bankers don't care about fiat, they care about making lots of money and buying expensive things. If bitcoin is the best way to achieve that goal, they'll be investing in bitcoin soon enough.
Big banks are manipulating the gold and silver markets hardcore to help the government support fiat. While its true that they also make good money with it, they are clearly on a government supported (or at least tolerated) mission.
So its not always 100% about making money for the big corrupt players like Morgan and Sachs, its also about keeping up the status quo.