It kinda seems like as a pop band and especially before Invisible Touch they put more emphasis on the backing music than Phil's singing (by "pop" I refer to any attempt at a pop song, though I consider Abacab the first real pop album they did). On "Taking it all too hard" and "A Job To Do" he yells out the refrain instead of a real vocal melody. But for the verses he still actually sings. Come to think of it, "Home By the Sea" has the best vocal melody on that album.

Even though Genesis didn't keep up the same quality they had with Gabriel, they were still better than their contemporaries who lasted into the 80's at distilling a pop/art-rock hybrid out of their "pure" prog because what was their idea of prog if not long "pop" songs anyway?

Side note: Phil had an interesting evolution as a singer. He relied a lot on multitracked vocals until Abacab when his growl-y style emerged. Then he settled into a watered-down, monotone voice around the early 90's.