Actually this ignores the fact that bitcoin uses ASICs now, and every ASIC built for bitcoin hashing is probably already hashing.
Semiconductor production can't be scaled up instantly, so 51% attacks require seizure of assets.
Even if the USA purchased every single CPU, GPU, FPGA, and ASIC made in the next month, it's unlikely they will have more than 10% of the network or so.
To seize the majority of the hashpower, they'd have to seize Chinese miners, which require either US-China cooperation or a world war.
I mean it doesn’t require ASICS, it’s just inefficient not to, right? Shouldn’t it be theoretically possible to mount a 51% attack with conventional CPUs (or GPUs), just a lot more of them? I have no idea what kind of computing resources various major states have, but I wouldn’t completely write off the possibility that they have enough CPUs to throw at the problem.
Semiconductor production can't be scaled up instantly, so 51% attacks require seizure of assets.
Even if the USA purchased every single CPU, GPU, FPGA, and ASIC made in the next month, it's unlikely they will have more than 10% of the network or so.
To seize the majority of the hashpower, they'd have to seize Chinese miners, which require either US-China cooperation or a world war.