Meetup is a resource for me. My guess that this change would complete end every single meetup I know of except for a few tech meetups - and these probably have alternatives and so wouldn't want it either.
It seems like this also illustrates a complete misunderstanding by the meetup company of how the meetup app is used by their users/customers. Among other things, it's standard for people to find group, sign-up maybe once and then not sign-up further but continue to attend regularly - the group I run and the group I've previously run were like that. Meetup was/is about discovery. Expecting potential attendees to pay is absurd, regular attendees wouldn't feel obligated to register and so wouldn't pay. The confusion is complete.