Infrastructure is what you ultimately pay for. making that more complicated (contextual, my ass) so that people might give up faster and "just use vercel" is very clearly the driver here.
Usually, companies even have guidelines what developers can use and how, probably none of these fancy new cloud-for-your-framework-aaS things are allowed. And often not running into just another lock-in situation has business value.
A great framework allows you to ship your code into multiple different infrastructure situations (on prem servers, kubernetes, aws lambda, ...) and "just work" by abstracting over the individual infrastructure specifics.
Also IaC is not a buzzword, you may have infrastructure engineers that already agreed on a specific tool (CDK, terraform, pulumi, ...) and have built extensions to deal with internal specifics of the company and really want to leverage them across projects.
Having something like the _framework_ dictate all that is like completely going backwards. I can't think of any explanation other than trying to promote that lock-in towards younger developers that haven't felt these pains of lock-in before.