Tirunesh Dibaba ran 14:49 for 5000 at age 16, Won the World Championships at 17, a couple of months ago she ran a 2:18 Marathon.
Lots of examples of runners who were good for a lot of years, Johnny Grey ran the first of his 26 Sub 1:44 for 800's at 24, Ran 1:43.36 at 35, and ran his final sub 1:44 at age 36 or 37
Steve Scott was also a top runner for OVER a Decade.
Tuohy will likely be running UNDER 2:20 for the Marathon when she is in her 40's, as everything improves, so if Cheromei can run 2:22 at age 41, certainly the training and diet will be improved in 25-30 years, likely means Tuohy will be faster than Cheromei is at the same age.
Tuohy = an improved and more talented runner than Cheromei, T. Dibaba, M. Defar, V. Cheruiyot etc. (All runners who were good young and are having long careers at a high level).
A lot of Posters had given up on Jordan Hasay now she is the 2nd fastest American Woman Marathoner EVER and she is still improving even Joan Benoit Samuelson predicts she will Smash Kastor's 2:19.36 AR, Everyone in running has ups and downs even Tuohy and J. Ingebritsen will have some bad times or even years, but the cream rises to the top eventually.