Actually it isn't. They didn't persue the Marvel license because they said openly during chats that it would require too much R&D because they didn't know how to do the spandex and the various bodies with their standard Buck. Then when Pro came around they said it still was something that they kept going back to but bodies, costumes were still in the way.
With the DC 1:6 figures they've said that they are creating entirely new bodies and that the costuming is no longer an issue. They are starting most likely with DC because it was a whole license grab when they went after the entire thing. Also I fully expect it to be higher priced because of the new bodies and all the R&D that has been done. Will people pay $200 plus for a Sideshow comic figure in comparison to an HT film figure? Or even close? That's a big question.
HT is doing Arkham City figures but Howard has mention Arkham Asylum a few times in his interviews especially when talking about Harley. SSC is doing a 1:6 Arkham Asylum Batman. That is a much bigger conflict than HT doing movie figures while SSC would want to do Marvel comic figures.
I would safely predict they are using the DC figures as a barometer and if the 1:6 figures are successful and sell well that you'll see a Marvel comic announcement sooner than later but so far the bodies are being used in DC and GI Joe and if they can be used for Marvel as well they just might be but this is a big gamble for SSC especially with HT and EB dominating the properties (despite it being from films) for DC. Even Medicom is dipping into the comic realm so SSC has to really shine and if they do, Marvel heroes are probably on the horizon.
