I think Darklord is right in that the newer, sometimes crappier movies get more attention because the studios want to publicize them, so the licenses are cheaper/easier to obtain. So, there are relatively low costs involved, and potentially high rewards because they choose those available licenses that they think will be attractive to geek audiences while they are in the public consciousness.
As for their older licenses, same thing. Some are probably more expensive (Predator/T2/Aliens), but they can guarantee people will buy enough to make it worth their while. Others are probably cheap, but have a potential audience large enough to make it worth their while to pursue (Mars Attacks comes to mind).
Long and short of it--they pick licenses and characters that they think will bring them profits--factor in cost of license, likeness rights, development costs, demand, etc. Some of those might "suck" to many of us, many won't.
As for wrestlers, we need Macho Man, Bret Hart, and Ric Flair before anyone else.