[peterhunt]

I think it's fairly common to swap out your core datastore when you take your prototype / MVP and bring it to production, or the first time your product experiences hypergrowth. At point the codebase, schema and team are still small enough that this is feasible. In fact I suspect every Firestore app that hits any degree of scale swaps out the DB for at least a subset of the app.

So I agree with you with this one important exception.