I think there are two things going on more generally:

1) providers increasingly adding hidden state that the user or developer cannot inspect, port, or do anything with. This is clearly bad.

2) providers increasingly diverging how they implement certain features and the APIs becoming quite complicated and provider specific.

The former makes porting sessions or transcripts impossible, the latter just more difficult.

IMO, it is fine and expected that provider APIs are starting to diverge and adding features that cannot be easily ported between providers. The time where the OAI completions API functioned as a universal standard is coming to an end. For example, I generally prefer the new responses API (minus the closed/hidden stuff).

The problem is that many product, library, and SDK authors are still pursuing the "unified abstraction across all model providers" ideal. Just stop doing that, and at least #2 is fine. You can still port parts of the session, but not everything.

I mean just think how difficult it is to add a unified abstraction across, say, databases: some products can do it, but the abstraction is still often leaky. Hence, we've come to accept that our data store layer is often quite technology/provider specific. It will be the same with model providers.

(edit: intro sentence)