Sure, there probably is a market for a UO style MMO in today's market and there are a number of small MMO companies out there working on them, but the vast majority of the time when I read these kind of threads by UO fans, they want a WoW sized game with WoW's budget and UO's style of rules and gameplay and that is not going to happen any time soon.
I do find it insulting to call fans of more forgiving games "carebears" though. There is no reason to resort to name calling just because someone enjoys a different style of game then you. The fact is video games are a business. They exist to make money. If a style of game was not popular, they would not be made. The MMO market is very competitive right now and people vote with their wallets.
Some day down the line, the popularity of "WoW-clone" MMO games will fade and maybe companies will be more willing to take chances with MMOs for all types of players from the really hardcore to the really casual. I really hope that time does come. More variety in the MMO market can only be a good thing. But for now, those harsher kind of games are mostly only going to be made by the smaller developers for smaller, niche markets.