The fallacy here is that any future mission would land near him. Mars isn't quite as large as Earth, but the odds of landing anywhere where a man could walk to meet a mission party are pretty slim. If you were stranded in Chicago (which you WOULD be if you were in Chicago), and a mission landed a mere 500 miles away, you would never even know it, let alone be able to make it there in time to be rescued. And what if the mission landed in Vancouver or Adelaide?
Or Buenos Aires...
In the book the next mission lands about 2300km from him.
This depends on how well they can control reentry and descent as well as the type of craft they are using.
Perhaps he makes a Segway from clock parts...