If bankers had a fraction of the faith/expectations/awareness in BTC as people here do, they'd be very concerned by it.
Fortunately, they don't.

By the time BTC becomes a real threat to them, it'll be too late for them to stop it.


BTW, you can't buy 10,000TH without raising the ASIC/GPU prices significantly.
Even if you develop it silently, your suppliers will raise their prices.

Also, putting additional hash power into the network will raise the difficulty.
Putting up a 51% attack will require much more than $10m.