The shift to Vue3 and a new paradigm (composition API) left the community in a state of confusion of where/how/when to migrate. The old paradigm is still supported but more like a legacy layer than the way to go. It reminds me of the python 2-3 schism.
I'm part of the community, several big production projects, several migrations from v2 to v3.
I was never confused.
The backward compatibility has a clean plan. For the bits that were complex changes, it was possible to do partial upgrades. From the beginning, the partial upgrade was in consideration. There was always early documentation, and you have access to v3 in alpha and beta all the time with complete documentation and complete guides. You also have standalone packages to start testing migrating bits of v3 to v2, like the composition API, class components, etc. It was one of the most seamless transitions I experience.
