You think the same can't happen for Bitcoin if someone builds a farm big enough to control 51% ?
No , that's not how bitcoin works. A 51 % attack can only delay processing or fake 1-3 transactions before being stopped. Full Nodes or users control the direction of the protocol. What this means is Bitshares has 100 delegates and Bitcoin has 20k+ "delegates" with the possibility of quickly amassing millions of delegates(Bitcoin QT with port 8333 open = full node)
What this means is that if the 51% miners get co-opted by any nefarious agents or governments(apologize for repetition) than a hard fork would appear and Bitcoin would remain the same and a new coin would develop. Their vote is essentially picking the Bitcoin code implementation they preferred and by not acting or upgrading they would create the hard fork.
Ok, my bad.. I am still learning.
What if an entity (a government, central bank, etc.) could maintain 51% of the hash power for an indefinite amount of time? Couldn't they repeatedly attack the chain? I find it hard to believe that sort of attack could be mitigated without switching algorithms and rolling back the block chain.