Already happened. All the agentic API dealers support x402.
I already pay some thousanth-of-a-cent for every webpage (pre-LLM era included) that my agents pull, simply for the privilege of going through a proxy with a squeaky-clean IP reputation (the fact that they charge by the byte keeps it clean -- scrapers can't afford that cost due to scale). That payment goes to the proxy owner not the website, but the point remains: I'm happy to pay that cost to eliminate hassles and headaches.
All that remains is to plumb part of that payment through to the website in exchange for a hard no-botwall (which implies no tracking) guarantee. It'll happen, and the websites that refuse will become irrelevant.
The future is bright.