At the time Phil said on more than one occasion that Genesis is Tony and Mike much more than him.
Now that history is written it's always easy to come up with ideas and assumptions, but I believe they never really thought this through when Phil left and didn't give it enough time to evolve.
they should have done some shows first, maybe in an unusual setting (semi-unplugged?), then record the album with Ray and maybe a second one.
It was clear from the beginning that CAS wouldn't be as successful as WCD, but they stopped at least one album too early, in my opionion.
The Ruins show was a special thing, since Queen, Genesis and Floyd did this together. Sadly, it was probably the final moment that caused Phil's decision to leave the band.
They were a bit clumsy, from a sheer marketing/promotional point of view. They waited too long instead of capitalizing on the buzz generated by Phil's departure, by the time CAS was released only a few cared about it. They should have given up any pretence of commercial success and with that in mind perhaps they could have been a bit more daring with the material. Nick D'Virgilio said in an interview that when he got on board, he was hoping they were going back to their roots a bit more. The tour should have been structured differently, ergo downsized and in hindsight, I don't think that Ray was the right choice, I like his voice and he did a fine job but he doesn't seem to have anything to do with Genesis music, some people were looking forward to him writing more on a possible next album. Personally, I dreaded the thought and I'm even more convinced after having listened to his solo material. I read that Big Big Train, David Langdon, auditioned, he would have been my choice. Great vocalist, somewhere in-between Peter and Phil and clearly, stylistically closer to Tony and Mike than Ray.