nothing would actually make it obsolete except chosing bad domain names...example: no matter what happens "restaurants.mobi" will be able to make BIG money...imo
also...as devices get more like these perhaps mtld can "change" the standards and that would allow the same experience as a .com (on these advanced devices)
Like your thinking about Mtld perhaps changing the standards should that need arise because of developments in mobile devices. I thought of that too. I think that would be the way to go then. .Mobi as a fully fledged tld accessible by both pc and mobile and offering the same experience as .com Plus the added benefit of having an extension that makes you think mobile.