Originally, ITV wanted Davina for the role (and she was close to signing). Phill said he would leave and they wanted him (kept the concept of the This Morning ‘Family’). He wouldn’t consider anyone other than Holly (because she was a star of smaller stature then and would let him ‘lead’). He got his way, the partnership (which had been tried and tested on DOI) worked and his power at ITV began (or rather, was underlined. He started with Ferne and ‘don’t take me down with her’).
Amanda covered for Holly during maternity leave and was (is) a strong personality. PS did NOT like and she was never asked to come back. Read of that what you will.
Rylan was very very popular with the viewers. PS did NOT like. He is also good friends with Ruth & Eamon and all were aware of the ‘runner rumour’. None of them were happy with the state of affairs. None of them had their contracts renewed. Read of that what you will.
ITV and Holly (plus senior management of TM) have defended him but the escalating bad press (QueueGate, I’m Gay and the brother) is not ‘on brand’. Of course, they can’t fire him for his brothers actions but they can, of course, decide to part company at the end of his contract. I’ll put money on the line being ‘I’ve had a wonderful time, but it’s right the series is taken in a new direction at this time of its 35th birthday and I want to pursue new opportunities’.
And HW can of course decide to protect her own career - a process she started by setting up her own management company, taking on BBC gigs and not being there when he came back after the trial. Shingles my arse