Hard fork to what? Gpu PoW? That doesn't work in an adverse environment, considering it would start from zero (gpu mining is almost going to disappear after mining eth ends). In fact existing asic miners could easily rent enough gpus just to kill the new fork by not allowing any transactions.

In fact when LukeJr made a threat of a PoW fork during the segwit activation drama, Chinese miners said they secured enough gpus to kill the fork when it starts.