For sure, I don't think they understand it.
The amazing communities of Reddit can recreate somewhere else - but that means Reddit will lose it's grip on aggregating the internet.
It's a good thing - it means that many communities will possibly go back where they should never have left (e.g. Manjaro forums is far more useful and less toxic than r/Manjaro).
What interests me more, though, is that once something gets posted on Reddit, it's instantly searchable - and that's an issue with Fediverse.
Interestingly, I just witnessed one example of a Federated instance being set up, received more than enough donations (basically, balance is now sufficient for 1 year with some extra to cover expenses) to continue.
We are entering a phase now where we must realise our internet isn't Free. It's sad, but true... we pay for our connections and that money doesn't get passed down to our activities.
Reddit is perfectly within it's rights - the 'community' are not the customer at all. They are there to be used... This 'FUCK YOU' pricing debacle is going along with the Twitter format - either make it profitable or let it die.
If it dies, then it's going to be up to 'us' (not me, I'm too dumb to set this stuff up) take over... However, if I found a nicely federated alternative which allowed me to access other federated sites, I don't see why every decent Reddit sub couldn't be created and linked in.
I don't even follow my subreddits on Reddit - I follow them on RSS, so they just appear as another feed - and only half my feeds are in Reddit - two of those have closed down, but (like c/dadjokes) some are appearing elsewhere.