I agree that the old Pixels are still excellent devices and would be perfectly fine for the majority of users... If it wasn't for the update politics. It's borderline planned obsolescence and while I understand the business perspective of this, it's just sad on so many levels.
I loved my Pixel 3a and would still use it today if Google and Qualcomm were willing or forced to keep them secure. But it is what it is, at least we arrived at 7 years of support by now, although I'm sure current devices would still excel in running GOS over a decade into the future (with a new battery which is not too hard to replace).
I think most people here are with the OP, it would be nice to use the perfectly functional Pixel devices from 5+ years ago. But we have to face reality, and security is too important to ignore, especially on the most secure and private mobile OS there is...