I like the idea of Sublinks for this reason. They wanted to create a Lemmy alternative, but they are maintaining Lemmy API compatibility. That way they build one piece at a time. The Lemmy frontend Tesseract was forked from Photon, and then became the Sublinks front end. But it's still also a Lemmy frontend because they work with the same API structure.
In addition, Lemmy apps all work with Sublinks as well.
This way, they could focus on just the backend component, and rely on Lemmy components for the other pieces until they are able to get everything in house. Though they have a plan to keep Lemmy API compatibility, so there will always be this big pile of apps and web frontends that can be used with both.