Did you read Scott Douglas's article in the last RT?
Sure you could -- you know what people do for real jobs? Things that are a lot harder than getting out the door and running in the open air for 15hrs/wk. If there are guys that will scrub out other people's shit 60hrs a week for $7/hr, you better believe that in a country striken with poverty, you'll find people willing to run 120mi weeks.
In it, there is a guy who had a knee injury. He could not run, got "treatment" that mess it up worse, and, when he found he couldn't run, decided to hang himself.
I can assure you, talk to Paul Tergat, Evans Rutto, Abraham Chebii, Eliud Kipchoge.
Initially it may be poverty, but there are some other options in Kenya and Ethiopia as well. Gebrselassie's brothers made it good as doctors and lawyers.
These guys at some point make plenty of money and can stop. But they keep going.
Do you think Tergat, after he won his 5th title at WXC in 1999, needed to keep running? World half marathon records, world titles, world record at 10K; do you think he needed more money?
He didn't, so why did he continue?