I think people will still keep on mining. Since the beginning it had always at some point cost more money to mine btc. Smart people mine even if it is for a loss, because they know at some point their investment will pay off and it will be 4 or 100x's more than what it costs now

But honestly with all the attention crypto has garnered in the last year and a half btc falling that low would cause a lot of panic in todays market I'm not quite sure exactly what will happen. But I do know that mining won't stop completely but maybe a lot of people will drop out of the pools.... maybe