Sorry you feel that way. For me, it's a fundamental part of what we do, and it's a big reason why I love working at Gandi. That's not to say all advertising is bad, but... what Bill Hicks said.
No - if pizza is owned by one TLD registrar www.pizza and great.pizza would be two separate subdomains under that TLD. I'm not sure there are limitations to the subdomain under the TLD (to prevent collision with www). Someone can register www under .com and make a www.www.com.
I wasn't saying they were interchangeable, just that on a technical levelhttp://www.pizza and http://great.pizza function in exactly the same way, as far as DNS is concerned.
Unfortunately, the same can't be said for most browsers, but that's another topic...
And I'm sure www is a reserved term under most of the new TLDs. Haven't checked though.