The increase in fees was quite sudden. If you actually have hardware non-active, it will take a bit of time (aka physical work) to reconnect them. I wouldn't expect large scale miners to have a large quantity of hashpower connected but not running. I'm not in the industry, but AFAIK mining hardware is no longer in short supply, so any available warehouse space and power infrastructure is probably fully utilized. So it takes time to scale back up again and reconnect previously unprofitable equipment.

That, or people expect this to be a shortlived experiment.