It also opened the door for a more premium non-Reddit app that charges monthly and directly competes with Reddit. From everything I've seen so far there might be enough of the existing Reddit community who are upset enough with the recent direction to make that leap viable and if the reported figures are accurate then the finances might also work if enough people jump ship to establish a new community.
Yes, but much like the "exodus" from Twitter, and others over the years - they all fail to reach critical mass. There's a very real early-mover effect, the likes of which have prevented Mastodon and even Truth from gaining huge ground.
Truth, being perhaps the most interesting, because the main personality behind it sort of compelled it to be semi-well-known simply because of media coverage. The other attempts do not share that effect, however.
They all fail to reach critical mass until someone does. That's always been the history of social networks. Once sites like Myspace and LiveJournal were everywhere. The next generation mostly went on Facebook and Facebook snapped up Instagram. Now a younger generation is on sites like TikTok. Digg and Slashdot are still going but they didn't stop Reddit becoming huge or more specialised sites with overlapping demographics (like HN for example) from building their own communities.
You're right that early movers have some advantage but it's a big world and the Next Big Thing doesn't have to win the whole market on day one - only enough of it to plant seeds that can grow over time.