Are you suggesting changing the client IP address between every request for every asset in a web page? Technically doable, but unbearably impractical. The new TCP handshakes, the new TLS negotiations ...

This is basically what TOR does. You can certainly do it, but as anyone who has browsed the web through TOR could tell you, the experience is significantly degraded. It's a lot slower, and many larger sites will ban you because you trigger their scraper/DDOS protections.

On Tor your exit IP address does not change for every request you make. Your address does indeed change periodically, but not constantly. The reason Tor is slow is because you're passing through many routers on smaller pipes (people's home DSL, for example) and sharing that with others using those routers.

No, I'm suggesting changing IP every time you get blocked.

If there was a large need for it there would be extensions that do it automatically (and with IPv6, you would have no shortage of addresses, which makes it easier to obtain new ones).