Now you hit upon an interesting issue. In NL we were more or less
forced a couple of years ago to open up registration for private
persons too, the reasoning behind it being 'fixed' e-mail addresses
even when people moved to another ISP, which happened frequently.
Initially we 'solved' this by introducing numeric SLD's (123.nl),
under which they could register names. That was not a success, to
put it mildly: all in all we registered less than 1000 domains of
that kind. Main reason: people didn't like the numeric "extension".
More recently .NL itself was opened up for private persons too, but
now we see a vastly different situation from a couple of years ago:
because of the massive amounts of spam 'fixed' addresses are not
en vogue anymore and lots of people have loads of addresses. Which
is just one reason why I don't expect TLD's to explode and a good
example of a problem that solves itself.
Interesting. While I've many times have seen spam described as a
problem this it the first time ever I've seen it described as a
solution to another problem ;-)