Building semiconductor foundries costs billions of dollars, takes decades and requires an enormous talent pool which is why almost all foundries in the world are located in east Asia, mainly China, Taiwan, South Korea and a little bit in Japan
the rest of the world is basically empty and don't have the talent or capital to build foundries
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.4cdn.org%2Fbiz%2F1610271676377.png&t=663&c=AZNBP3NZeyMeKA)
also should keep in mind that China doesn't even need 51% of the hash rate
there was a study a while ago that pointed out the fact that a determined attacker might just need 21%, the attacker could use dump his btc, lowering the price, forcing commercial miners (who need to be profitable) out of the game and slowly growing his initial 21% to 51% without actually acquiring more mining equipment
take a look at my picture, notice anything? why do you think they are so determined to take Taiwan? the sightseeing?