You aren't wrong. A lot of it was because Columbia/Sony had the rights to Spider Man. Fox had X-Men/Daredevil/F4, Hulk was at Universal, and no one really had anything else until Disney bought all of Marvel and kicked off the Avengers series. Those older licenses were all pre-Disney buyout when Marvel was just trying to stay afloat, and they were selling out licenses for their IP as they could - so you see different comic characters at different studios. Now Disney is trying to slowly get them all back, since they own the mother company now.
Once superhero movies became the de-facto "cool thing", yeah, all those studios that had licenses that they hadn't really done much with, all of a sudden wanted to cash in and rebooted it all back up.
We are probably due for another Batman reboot since DC universe has pretty much only survived on the Bat... Oh, look,
right on cue.