Part of the problem is that RPG licenses don't really have much to offer to videogames these days. Look at something like City of Heroes. If it had been a licensed Champions game, would it have been better off? Even without an established name behind it, it did fine enough on its own.
Really, videogame makers have two choices:
1) Use a licensed IP for their game, which comes with the risk of legal issues and creative control from the IP holder.
or
2) Create their own IP, which may be licensed out to other people later for profit.
In order for choice one to be worth it, the benefits need to be outweighed by the possibility of the licensed IP drawing in a large pre-existing fan base. Unfortunatly, the fan base of most table-top RPGs is not big enough to make a license really worth it most of the time. It takes a very powerful IP like Star Wars to attract highly skilled videogame developers.
Really, videogame makers have two choices:
1) Use a licensed IP for their game, which comes with the risk of legal issues and creative control from the IP holder.
or
2) Create their own IP, which may be licensed out to other people later for profit.
In order for choice one to be worth it, the benefits need to be outweighed by the possibility of the licensed IP drawing in a large pre-existing fan base. Unfortunatly, the fan base of most table-top RPGs is not big enough to make a license really worth it most of the time. It takes a very powerful IP like Star Wars to attract highly skilled videogame developers.