yea that was just a horrible period of what marvel was trying to do then. as you see as soon as they got the rights to the xmen the inhumans went to being virtually non-existent.
I know he didn't appear in other books, as we know Wolverine has been the mutant face across the company for eons now. however, Cyclops was still very pivotal to the stories told for years even before Xavier fully left the picture. I know his fans want to see him in beyond being captain cameo but he's definitely had his fair share of stories to allow others to take center stage while he just enjoys life. though I'm sure he will be more active again once his team gets fully off the ground
I dont believe I can find any reason why this would make sense. there were clearly a lot of cyclops fans during this period in the creative side of things lol.