I remember vividly when the digg exodus happened, I don't ever remember a single person complaining that reddit, nor digg, were too technical/difficult to understand/use.

Both sites you simply clicked the register link, input your username/pass/email then done. The fediverse does not have a clean onboarding that lends itself to comprehension by a regular non-technical person. It seems way over the head of your average user. I've tried to get friends to check out Lemmy and it's a solid no-go.

If you need an entire matrix of understanding of a concept before feeling comfortable to use it then it is simply too much cognitive friction.