What "support" does Google need from Qualcomm after three years beyond driver/firmware blobs, which three years into a SoC's lifetime should be pretty stable?

We're talking about a company that maintains its own fork of the Linux kernel with something like 19,000 patches against mainstream. Anything not in a blob should be easily within their abilities to address.

Also, Nexus and Pixel devices have a long history of software and hardware problems, many of which are immediately obvious within a day or two of devices hitting people's mailboxes, and are never fixed over the life of the phone. It's not like google seems to be picking up the phone very often to talk to Qualcomm for support, even during a device's development, much less after?

The Pixel line jumped the shark when Google started permanently carrier-locking phone bootloaders for Verizon.