I do agree that the average Redditor will not only not switch, but will probably continue to use Reddit, at least until the 30th. We'll see what happens after that. That being said, I think that's a good thing. Reddit has 500m MAU. Not sure the fediverse is up to the task just yet.
In the meantime, Lemmy as a platform can benefit from this by fostering a solid community from the refugees that do make their way over. I imagine there's a fair few software engineers who may now be interested in working on this project, which I think will be healthy for things in the long term.
I think the fediverse is inherently different than the "normal" Internet. The way I'm thinking about it now is that each instance is a bit like it's own town, and the activitypub protocol is the road infrastructure connecting each town. There may very well be a group of technologists in Town A, but that shouldn't stop anyone from making their own group in Town B.
That being said, it's very beneficial to be able to gather all of these disparate communities into one place, and going back to the analogy, this would be something like a city center, where many people from smaller communities come together.
Perhaps in the future, we'll be able to create our own feeds (i.e not just subscribed, local, and all). I think that would be a solid way to handle things. Bonus points if those feeds can then be shared with others, so that they don't also need to go through the work of finding and subscribing to the individual communities that make up the greater feed.