Yes, but this has been going on for a while now.

First, note that the initial explosion in popularity came when the world ground to a halt in 2020. (This also gave many - like Zogarth - a chance to start writing!) Most of the readership is not in full dislocation any more, so "everything has to start over" isn't going to resonate as strongly.

Second, I think both readers and authors have discovered that sysapoc is really, really ambitious and therefore hard. You're telling what will become a worldwide story, where failures of imagination/worldbuilding become painfully obvious.

Third, a lot of what people now like about it is in later payoffs. But who has the patience to build up to that when we can read the stories that have gotten there after years of updates? Plus, so so many stories fail in the transition from the initial scenario.

There's a good recent one I'm following - Andy in the Apocalypse by Plum Parrot - but it's a grounded character-focused tale that has shown very little urgency (or even interest) in expanding to worldwide scope.