No, they won't stop hashing. Most miners will not be using asicboost right now because it requires software that does the preprocessing for asicboost to be used with the miners and a different firmware on the miners themselves to be able to use asicboost. Furthermore, the stratum protocol is incompatible with ASICBOOST (at least the covert version, which is what is apparently being used) so people who are using antminers are not using asicboost right now, and making asicboost impossible to use would not effect them.

Disabling ASICBOOST by a protocol change would make the miners operated by Bitmain and those who received the special software and firmware from Bitmain would only make asicboost unusable and thus take away their advantage. It is unknown who is actually using asicboost besides the miners operated by Bitmain.