Spreading the word about it and maybe simplifying the process a little is good, but I don't think the goal should be to become mainstream. Then you just end up with Reddit again, fediverse or not. Having a small technological literacy test to filter people out and keep communities somewhat small isn't necessarily bad, it keeps things higher quality and focused by ensuring only people willing to put in at least a tiny bit of effort join. Like how, on Reddit, the "default" subreddits were complete garbage, but the smaller communities people had to put in some effort to find actually tended to have good content.