Another bad idea that keeps coming back. Real experts have written about it. Start with https://humantransit.org/2019/08/what-is-microtransit-for.ht... and be prepared to read for a while to understand why this is not a good idea despite the hype.
Even the NPR article says that larger cities are experimenting with micro transit but only for harder-to-reach areas.
It has a place as a complement to fixed route transit, not as a replacement.