Maia: History & Literature (I know some people will roll their eyes at this, but consulting and banking firms truly don't care what someone majored in at Harvard so long as they have a high GPA, interesting resume highlights, and good people skills.)
Ky: Management Science and Engineering (can be specialized into essentially a tech-focused business degree)
Yared: Biochem
Sage: Chemical & Biological Engineering, pre-med, stats minor
Joe: Biochem
Olivia: BA in Marketing, MS in Business Analytics
Mario: Chemistry
Neither of us can predict the future, but you sound absurd and bitter saying that "none of the above look promising." Truly, what can you point to that makes you think these people could only pursue coaching after they're done running? When it comes time for them to leave professional running, they'll be able to tell interviewers about how their running careers required performance under pressure, long-term goal seeking, time management, and persistence through adversity (you don't have to "buy" that spin, but that's obviously how their resumes will look and what their interviews will sound like.) These are athletes that are used to being high achievers, tend to come from high-achieving families, and likely have some connections amongst their friends, parents, and running fans in their alumni networks. Most of them (primarily Maia, Yared, and Sage) demonstrate interests outside of running, and don't seem like they'd be fulfilled if they only pursued coaching for the next 40 years (though, if they did, would it really be so bad?)
I picture many of the OAC crowd following in the footsteps of people like Kori Carter (2017 World Champ to Wharton to strategy at Nike) or Donn Cabral (2016 Olympian to law/business dual degree). I'll be shocked if Maia doesn't end up at Fuqua, Wharton, Stern, GSB, etc. Sage may not decide to go to med school, but why can't you picture her working for a biomedical research company? I don't have any personal stake in this, but the most likely second careers for the more "academic" OAC athletes would seem to be in non-running fields, just based off the profiles of similar athletes.
Also: Sage has been out of school for four years, Yared for three, Joe for five, and a few of the others for less. Your hyperbolic statement about them doing nothing with their degrees for ten years doesn't aid your point.