So ultimately this leads to situation when blockchain grinds to halt every two weeks of four. Will not happen. If needed btc core will be patched to calculate d

So ultimately this leads to situation when blockchain grinds to halt every two weeks of four. Will not happen. If needed btc core will be patched to calculate difficulty in some other, tamper resistent way, and miners WILL ACCEPT this patch gladly. This attack can be pulled off in economically satisfying way only then your electricity costs dominate your overall costs, i.e. you do not pay rent, wages etc. And this is false. Given miner's situation (he pays wages and rent) to use this attack effectively miner needs to represent significant part of hashing power of network. This means that his stakes are high and engaging in destructive behavior may undermine reputation of Bitcoin as network, BTC price and ultimately miner's own business. In case lower scale attack (manipulation of hashing power of a pool) pool and his operators are there to punish such behavior. EDIT: language