Ends bitcoins decentralization

This has no effect on Bitcoin's decentralization. My node will continue to find blocks independent of any banker's interest. They might save themselves from economic doom by adding to their balance sheet but they won't control anything.

Futures market

I don't disagree that the wealthy have been able to control silver and gold. The problem for them is that Bitcoin isn't the same beast. See how well their rehypothecation plays work on proof of keys day and we see these third party custodians caught with their pants down. They might be able to do things in the short but that will only expedite the time without them.