I mean ones where you would put goggles on
And then you would be inside a truly 3D virtual world. And you would meet characters etc and interact with them. And go to places etc.

That actually seems easy. It's just like doing a game like in WII or Xbox.
The only thing they would have to do is create the expereince inside the goggles and then make it so that the user feels inside(with sound etc) and all the world reacting to his actions.

Seems quite easy . Why they don't do it?

It's probably not as easy as it sounds. It is also probably quite expensive to do this at this point in time.

There were plenty of movies and TV shows in the past that showed this sort of thing as fiction but I don't think our technology is there yet despite how it may look easy to do.

Hello George:

If you're a young man, I believe you'll see what is TRULY a virtual game during your lifetime. One that you wear a hood or visor ISN'T truly virtual.. Truly virtual would be when you turn on the game, the participants appear in your living room. They interact with YOU. You can TOUCH them, and they FEEL real. They can touch YOU and it feels real. Think holodeck on the Starship Enterprise.

I'll leave the rest to your imagination.

excon

Do you have any experience in programming? What makes you think they haven't been working on it?

In Die Another Day (Bond movie) they show Bond going through a virtual training exercise. But this is fiction. It doesn't mean the technology exists. It is being worked on, I think by the end of this century, TVs will no longer exists but be replaced by holographic projectors. This is all tied together.