At what point did running really far become the thing to aspire too when getting fit?
What about strength? Speed? Flexibility? Agility? Regardless of the evidence, most people are better served doing a good mix of activities and being generalists.
The only reason to run more than 10km is if you like running. Otherwise 5-10km at a decent pace is just a good cheap way to get effective cardio. You should probably stop there and lift something heavy.
I think well-roundedness gets overlooked because our culture is one that lionizes those who push themselves to near-death in a certain specialization, so you get a segment of people pushing themselves harder than is holistically healthy.
