I guess you don't realize that Marvel Studios (who does the Marvel Cinematic Universe) is not involved with this, and thus they are not responsible for any perceived "bastardization"...
In the 90s (I think) Marvel was on hard times and sold rights to various properties to keep from going bankrupt. As such, Fox owns movie rights to Fantastic Four and X-Men (anything mutant related). They also had Daredevil, Punisher, Blade, Ghost Rider, and others but let those revert back to Marvel. Sony has things Spider-man related. Marvel has no say over casting, stories, release pace, costumes, etc. for these franchises.
Marvel Studios has the rest (but only after Disney bought them and brought Hulk and Iron Man home from Paramount), which is squarely centered on Iron Man and the Avengers.
It's a lot more complicated than that, but I think that's the basics.