Right. The protections against this are already baked into the protocol.
51% attacks don't make sense because you're hurting yourself 51% and hurting everyone else 49%.
And for this theoretical attack you'd probably need to sustain 90%+ hash power for a long time.
Your first hurdle will be producing enough ASICs to surpass current hashrate by nearly 10x. Solve that problem and you'll need a massive amount of energy and you'll have to set up huge mining facilities in various locations to prevent crippling local power grids.
This would take years to plan & execute. A lot of people would have to be involved. Good luck keeping it a secret. Network hash rate will continue to increase while you're building this infrastructure.
If by some miracle you've pulled this off, Bitcoin users will switch to a fork of Bitcoin that uses a different mining algorithm and your entire investment is now completely worthless.
The protections aren't baked into the protocol because they don't account for external real world motives of nations states which could incent them to act in a "non-economic" way according to the internal rules of the Bitcoin game.
It's baked into the incentivization structure, if you prefer it worded that way. Investing hundreds of billions of dollars and years of work to place a temporary speed bump in front of Bitcoin's growth doesn't make sense.
This isn't a temporary speeedbump, it's a permanent end to proof of work mining as an investable activity (and viable sybil resistance mechanism for bitcoin).
Remember UASF? If incentives align amongst users, nodes, merchants and exchanges Bitcoin absolutely will switch to another mining algorithm and now the attacker has to start from 0.
If the attacker attempts to keep up the game of cat-and-mouse long enough they will eventually go bankrupt and will no longer be able to participate.
And this theoretical discussion completely dismisses the fact that it's nearly impossible to execute an attack like this at this stage in the game anyway.
UASF effectively became a negotiation between honest miners and fullnodes. Honest miners are incentivised to close off conflicts because it risks devaluing their future rewards. In this scenario the attacking miner is acting "non-economically" so it's nothing like UASF.
51% attacks don't make sense because you're hurting yourself 51% and hurting everyone else 49%.
And for this theoretical attack you'd probably need to sustain 90%+ hash power for a long time.
Your first hurdle will be producing enough ASICs to surpass current hashrate by nearly 10x. Solve that problem and you'll need a massive amount of energy and you'll have to set up huge mining facilities in various locations to prevent crippling local power grids.
This would take years to plan & execute. A lot of people would have to be involved. Good luck keeping it a secret. Network hash rate will continue to increase while you're building this infrastructure.
If by some miracle you've pulled this off, Bitcoin users will switch to a fork of Bitcoin that uses a different mining algorithm and your entire investment is now completely worthless.