Internet connected TVs lack browsers

You would think this would be a common feature on TVs these days, especially since most TVs have apps. Why is it so hard to just get a web browser built into the TV? 

Connecting the computer to the TV isn't really an option since it requires so many accessories, such as cables and wireless mice/keyboards. I know that some Samsung "Smart TV Advanced" features a full web browser but besides those, the only browsers I know of are the ones that are built into game consoles, which kinda suck. The Google TV has one but it's unusable since so many websites are blocked. The Apple TV would have been a fine option but since Steve thought everything besides the content available in iTunes was "amateur hour", a Safari app was not included.

I really can't be the only one who doesn't want to deal with connecting the computer to the TV to simply get a web browser on the big screen, so why is a full web browser built into a TV so uncommon?