Why lock-in? The interface is just a conversation and the non-programmer won't know whether it's InstantDB or whatever else in the background, as that's the whole point of vibe coding. I can only see issues taking out your data into another system, but even that can be vibe coded (can it?)
But hey, rewriting the plethora of vibe-coded long tail* apps might be a major source of employment in the future.
* small but loyal and profitable userbases