I mean, it kind of did. When Digg imploded Reddit received a massive influx of users over night. At the time and with Digg out of the picture there just wasn't a good alternative to Reddit (slashdot and fark to lesser degrees) so they had the whole market to themselves. Similarly a lot of us came to Lemmy overnight when Reddit turned off their apps. The difference is, Reddit for many many users is still good enough and fundamentally the same as it's always been.
The fact is though, without search traffic the only way to end up on Lemmy is knowing it already exists and that's going to hinder growth.
Definitely. Luckily the fediverse by its nature is somewhat insulated from becoming a company with a CEO like Reddit.