Except if you read the experiences of people who get the sinus surgery, it's not a permanent fix and it can go horribly wrong. It just buys one a few years of relief while the creeping crud finds another way to make your life miserable again. You're right that both approaches assumed there was a mechanical/stuctural fix to the problem. It's just that mine was less invasive and IMO the correct first step.

As for the root cause being viral versus bacterial, I suspect it was pneumonia bacteria. There was a frequent peroxide smell to my mucus and said bacteria were cultured repeatedly from the crud.