A cap would be impossible to enforce; ICANN can't monitor someone forking over the cap + a briefcase of cash between two buyers god only knows where. And super

A cap would be impossible to enforce; ICANN can't monitor someone forking over the cap + a briefcase of cash between two buyers god only knows where. And super-valuable domains are minuscule portion of overall domain sales, it simply wouldn't be worthwhile. And it need not be a "sale of a domain" at all; it can be the sale of "ww.com corp", which owns the domain, without any domain transfer at all.