Sounds like he
ran out of desire
Best to quit while you're ahead. He only had a 2yr contract anyway. He's one of the standout riders of his generation and he'll never be able to beat winning the Giro on stage 20.
That's coming from Visma though.
I watched an interview with Yates from only about 5 weeks ago from the Giro presentation.
He was saying how keen he was to return to the Giro and defend his title, and how rare it was to get the chance to come back with a No1 on your back.
When asked about the chance of Jonas riding it and him having to slot into a supporting role, and how he felt about it, he basically didn't answer and said that a load of discussions were in progress (He may even have used the word painful) and that it would be decided in due course.
He certainly seemed fully motivated at the beginning of December, unless it was all an act.
My theory (And that is all it is) is that he did want to defend his title, and maybe gave them an ultimatum of sorts - either you give me full leadership and support at the Giro, and I'll support whoever you need me to for the rest of the year, or I retire.
Jonas is clearly the future for that team, and at present the only rider capable of taking any more TDF titles, so I imagine he pulled rank, and they had to say to
Adam Simon it was a support role or nothing.
Shame, as clearly he was in stunning form last year, and no reason to assume he would not be in a similar place this year.
Good shout with Ineos, would have been good for Onley, but I imagine due to him being under contract, that wasn't ever going to be an option.
EDIT: Of course theoretically Ineos wouldn't be able to sign him as he missed some scheduled doping tests way back in the day, and Sky as it was then, said they would never sign a rider with anything hanging over them.