I see that Monero is stronger on privacy space. But the attack you are saying can be done on Monero or on any blockchain. The problem is, which country has the money to build up this 51%? It is not as if buying 1Mio Bitaxe would be the same cost as buying 1000. At some point there is no chip on the Market and the state to commit the attack would need to build new chip fabrication to execute this attack. So this problem increases security for Bitcoin extremely.

On the other side normal miners get less rewards, when a state goes big in mining, which incentivizes current miners to lower their mining capacity, which weakens security.