I think a platform team taking ownership is the correct model, but the early product teams need to have "embeds".
The platform team owning base terraform functionality works well for the product teams that are the 3rd or 4th user of said functionality.
For the early days of the platform, and the early users.. your product is constantly in dependency & priority battles with said platform team. This is where "embeds" help continually unblock while making sure the work is done in a platform centric manner that will be reusable for other product teams.
Simply saying the product teams need to go down into the weeds at this level just puts too much disparate responsibility on product teams who exist to deliver a single product. Similarly it encourages vastly different approaches to similar problems, with all the wasted duplicate & re-work.
I tend to think of embeds as being very similar to the open source contribution model: you want some sort of BDFL entity that drives the overall direction of the platform, but also some sense of community/collaboration where individuals can feel empowered to contribute features to scratch their own itches, or bring up discussions, etc.
Having a team owning the platform doesn't necessarily need to mean shutting yourself in a cave. Granted, promoting cross-functional collaboration is a challenge in and of itself, but similar to OSS, projects that invest in the community aspect are the ones that eventually gain critical mass and set themselves apart from the rest.
The platform team owning base terraform functionality works well for the product teams that are the 3rd or 4th user of said functionality.
For the early days of the platform, and the early users.. your product is constantly in dependency & priority battles with said platform team. This is where "embeds" help continually unblock while making sure the work is done in a platform centric manner that will be reusable for other product teams.
Simply saying the product teams need to go down into the weeds at this level just puts too much disparate responsibility on product teams who exist to deliver a single product. Similarly it encourages vastly different approaches to similar problems, with all the wasted duplicate & re-work.