MVNOs don't exist because of regulation - they exist because some wireless carriers have decided that they'd rather sell wholesale access to their network instead of leaving the market entirely to their competitors.
I don't have a problem with the lack of unbundling. I was a Covad customer for a number of years, and it was atrocious - whenever there was an issue, Covad and Ameritech/SBC/AT&T would go round and round with finger-pointing. Later, when AT&T began their U-verse (FTTN) deployment, Covad was shut out, stuck with the longer copper lines all the way back to the CO.
I don't have a problem with the lack of unbundling. I was a Covad customer for a number of years, and it was atrocious - whenever there was an issue, Covad and Ameritech/SBC/AT&T would go round and round with finger-pointing. Later, when AT&T began their U-verse (FTTN) deployment, Covad was shut out, stuck with the longer copper lines all the way back to the CO.