I actually view it the opposite. Lemmy isn't necessarily doomed from the start but we will not reach mass adoption because we are too clunky to use for most users because of its distributed nature.
Bluesky has enabled tons of non tech users to immediately reap the rewards without having to worry about instances or who can see their posts, while maintaining decentralization (albeit with a high cost).
The true path forward will probably be a world like Bluesky but instead of running your own relay, you're contributing compute power to a Kubernetes cluster. Instances and having to worry about federation is far too clunky for most users, it's the reason mastodon never saw mass adoption while Bluesky almost immediately did.