IIRC, this license came from Sony and not Marvel (or is it that Sony has the license to movie-related games and Marvel has it for non-movie ones?)
Sony just has the rights to Spider-Man as it relates to film (Marvel sold the film rights wholesale back in the late 90s, a decision it likely regrets in hindsight) and Acti was contracted to release tie-ins to the Amazing Spider-Man movies. If that partnership had conferred Acti access to the Spider-Man IP in general, then Shattered Dimensions would have hit Steam sooner as the app is actually at least ~two-and-a-half years old. I'd guess that Acti was prepping to release Shattered Dimensions on Steam following the release of the first TASM game but was informed that its agreement with Sony didn't cover the entire Spider-Man IP; fast-forward to now and Spider-Man is covered under Acti's existing contract with Marvel that saw Deadpool unexpectedly resurface.
Edit: I'd forgotten that the Wolverine game is a tie-in to X-Men Origins: Wolverine, which is a Fox film. I don't see Acti going the extra mile for the sake of a Steam re-release. Hopes deleted.