Agreed EEE doesn't need to be strictly technical (but it certainly could be! See the example of increasingly complicated and quick moving web standards driven largely by Google which makes creating a new browser so hard).
But a UX path could easily look like:
Find the top 500 lemmy communities by size/engagement. Create those communities before the server ever opens up to the public. Pre-poulate with content.
As people join, sort them into these communities based on their FB/Insta/Twitter/Threads profile. Indicate in some way that their existing contacts are into those things too and "may" be there to encourage adoption. Open up to federation.
Voila, f/linux has 200k users in the first month all chatting and posting. People like content, so native lemmy users subscribe and start engaging over there. The UX is great, very polished, etc. Maybe they create an account migration tool.
A while later, BigCorp decides it's time to pull the rug, defederates (for whatever reason, probably moderation issues), and now everyone who's still a Lemmy user is cut off from the communities they followed and the "native" Lemmy communities are tiny and quiet. Lemmy users cry foul, and no one cares because Big Corps get to set the message and for some reason people come out of the woodwork to defend them.
Facebook has no incentive to Federate (seriously for what?), but has insane incentive to kill a federated service before it gets off the ground or ever grows to be anything approaching the size of reddit.
I acknowledge Threads is a bigger problem for Mastodon, but you would be incredibly naive if you think there wasn't a team of people working feverishly at getting a FB owned ActivityPub targeted at a Reddit replacement. It would even integrate with Threads, like Kbin has microblogging.