I didn't see any performances on this tour, but I've seen enough YouTube videos and interviews to appreciate how frail Phil is. I do think it's time he retired (not enough performers retire) and everyone can remember him for the great singer and stage performer he was.
We can never know what goes on behind the scenes, but Genesis seem to have had a very stop-start live career, with very long gaps between tours. Obviously we wish Covid and Phil's health hadn't got in the way this time, but they should have done this tour years ago.
I think the reason why it didn’t happen years ago is due to a number of factors: Phil “retired” after his Going Back solo record in 2010, went through some personal & health issues during retirement between 2010-2015 as detailed in his autobiography which he published in 2016, started to re-release all his solo albums starting in 2016 after re-mastering them with Nick Davis, got the itch to come out of retirement in 2016 and did so from 2017-2019 for his Not Dead Yet tour, which finally paved the way for this reunion/tour to happen after it became obvious that his son Nic was capable of handling the drumming duties and after Mike performed with him on stage during a show on the solo tour.