Therefore congrats to Mick on the agreement with Mercedes. He is a Schumacher and even this is enough for me to believe in his future to be much better than this. Michael Schumacher also had a career with Mercedes in the past. This is a nice coincidence because of that. I hope Mick will be able to show his real strength when he has the chance.
I think Ricciardo kinda lost his passion to drive or at least to be a top driver. Also he screw himself up big time when he chose to go to McLaren as I don't believe in the RedBull fairy tale with him so I still believe leaving Redbull was the best decision at that time. I also think he will not be back in F1 anytime soon or anytime at all and most likely Mick will have it's chance to step up in Hamilton shoes and take that car for himself in the next years but it all depends on what improvements he can get by being a reserve driver for Mercedes.
Ricciardio is not very old in itself. He also raced for a while together with Max Verstappen. Then you are also unlucky that you ride with someone who clearly has more talent. After that, he never came back to the top. He is a very sympathetic driver, but that is of little use in top sport. Verstappen will still stay with Red Bull, although I heard that Mercedes and Ferrari were keen to have him. Verstappen is also someone who is loyal to his team, he will not switch to the competitor for a few euros. He would really lose a lot of fans with that.