It's actually and interesting question. Nurmi was paid and eventually banned for it. Zatopek, like all Eastern Bloc runners was paid but not officially as an athlete. They'd have been banned if they were so they were mostly either in the military, where their assignment was to train and race, or students, generally in phys ed and given "stipends."
Then you get to guys like Gordon Pirie and Michel Jazy. They had real jobs but with employers who supported their running by paying them full time for part time work. Japanese corporations did the same thing for runners on a larger scale.
These kinds of arrangements never caught on in English speaking countries (Pirie's situation was fairly unique) so you could say any of us who were out of school and ran before legitimate prize and insurance money came along were hobby joggers. But there was still money to be made. Ron Clarke did VERY well with expense money but he'd tell you he never made money from the sport because what he made compensated for what he lost due to time away from work. If you were a big enough name back then you could do well as an amateur through expense money. So maybe you couldn't count all of the people from those years as hobby joggers but none were running for the money.
Lots of us did occasionally get a few bucks to pay our way to races. But most people from that time didn't make much expense money, ran because we wanted to and looked for ways to stay alive that allowed us to train and race as we wanted to.