I don’t think these MCPs are bundling as usually defined .. you have to pay Supabase et al separately not through ChatGPT

Fair point. In the classic economic sense, bundling means one price for many things: Office, the cable package, Amazon Prime. And you're right that Supabase, Stripe, or Dropbox still bill you directly, not through ChatGPT.

But I'd argue the bundle that matters most here is the interface. I made a similar point back in 2017 when Apple started letting developers build apps inside Messages, Maps, and the share sheet: what does bundling really mean in those situations? An app isn't really an app. It's a set of notifications, a custom keyboard, a share extension, an integration in a messaging service. Nobody paid Apple for Gboard either, but Google search was still being pulled into Apple's surface.

The same thing is happening with AI clients. The jobs that used to happen across separate tools increasingly start (and often end) in one chat window. That's where the leverage shifts, even if the invoice doesn't. When your service runs inside someone else's client, how your app can be found and used is managed by that client, and since it manages context throughout the task, you lose the ability to see and use that context to improve your product. ChatGPT Apps also come with design guidelines and developer requirements not unlike those found in other app stores, and we all know how app stores eventually approached payments.

So yes, maybe "aggregation" is the more precise word for what plugin directories are today. But owning the place where people start their tasks has historically been the first step toward owning a lot more of the relationship. Billing tends to come later.