So, please tell me, who can buy 15% of the hash rate, in what time schedule? It's not like, I go in the store and say: "Here is 1 billion dollar, one 15% of Bitcoin hash rate, please".
Still, nothing about my other counter arguments.
if i was a gov or a central bank i'd probably get all the hash i wanted. If nobody would deliver to me i would have the recouces to build my own asics. Does this even need to be explained?
So, they would compete with all the other ASIC-developers.
You can't enter a market as a newbie and become one of the big players in a short time.