The amount of moves possible doesn't necessary give a good indication of the difficulty of the game. Consider for instance tic-tac-toe on a billion by billion board. Far, far more moves possible than on a Go board. Any computer program that would "look at all the moves" would take too much time. Yet the game is a simple win for whoever goes first.
I'm not at all convinced that the fact computers are "futher" in chess than in go is purely because of the number of moves to consider (and your numbers for chess are way off - in the opening, both white and black have 20 moves available, giving 400 different positions after the first move. Of course, still less than the 129960 different go positions after the first move). I get the impression more people are interested in chess than in go, and more research in (computer)chess has been done than in (computer)go. Which will also contribute in the difference.
Personally, I don't find the discussion whether go is more difficult than chess (why is it always go players that bring this up - at any game site I go to, some go player has to come up with this - it's like Python or PHP saying of their language that it isn't Perl) interesting. I know the rules of both games. I like to play one of them, and I don't find the other interesting.
Anyone fancy a game of Catan?