I claim the problem with the first big expansion - .pro, .info, etc - is that it WASN'T wholesale. Yes, if half the Internet thinks that only .com exists, and you add .biz, every corporation has to go register .biz as well.
If you add a thousand real, active, well-used TLDs, they don't, simply because that is no longer how the Internet works. We already see the start of this with ccTLDs; Apple (a pretty aggressive trademark defender) does not own http://www.apple.fm, and nobody expects them to, and nobody is confused that they don't. I'm sure my grandmother sometimes confused Elvis Costello with Elvis Presley, but nobody thought the one was impersonating the other, because people have last names, and that's how it works, and that's normal.
Five years ago, the average American non-technologist's mental model of the Internet was "you type the company name and .com, except sometimes it's .net and I don't know why". Now it's probably a little more nuanced - but only a little, because .com is still Where Everything Is.
If you change that, you've changed that. Because you changed it. So it's not the same.