Meb ran his marathon PB at, what, 37? & then made the Olympic team at 39. Competed in Rio at 40.
I'm not a big Rupp guy but he was always our best bet at the 10k on the track and on the roads when he made the jump. He's 36 now. I don't know how healthy he currently is. He's done Boston a bunch -- maybe he wants a crack at a faster course. Still waiting on Tokyo/Rotterdam/London fields. He ran 2:09 at Worlds, before dropping out at NYC. He's maybe done in that it'll take a lot for a PR the next few years. It's possible tho. & it's very possible that he goes for & makes one more Olympic team. Very few US guys can run 2:09. Rupp knows how to race. You're not time trialing at the Trials. If he's just trying to get in the top-3, I still like his odds.