It's been a bit more than a year and it's still active. The developer was even granted a Developer Transition Kit for the new Apple Silicon, to test his new apps (despite, AFAIK, only having made apps that aren't available on the App Store). The app also takes advantage of the free 7-day development deployment rule, which is something I can't see Apple being able to change without alienating new devs from their platform. It would also be a bad move, anti-trust wise.
It's very, very clever.