@ZiptieZoe @atomicpoet @gisiger I agree many will, just as a number of people choose indie email services, often for ethical or privacy reasons. Though those email services generally keep exchanging email with the big providers, who serve the majority of email users and are cheaper & easier to use for many than most indie email services.

Any instance can of course refuse to federate with any other. But it'll be a very different experience on narrowly federating instances than on broad ones.