Rudas
Certainly, many pilots started their interest in aviation by hanging out at their local airport, and visiting air shows. As to how many were 'spotters' I don't know, but certainly some were. I certainly was in that category for several years, but soon found aviation photography to be more interesting.
There was a thread on this topic some time ago in the 'private flying' forum. The consensus of opinion seemed to be that the 'real' pilot should march to and from his/her aircraft without even a glance at the other interesting hardware parked on the apron! In other words, even showing an interest in another aircraft was evidence of that terrible crime, aircraft spotting!
I don't believe this attitude represents the majority in flying, just the opinion of a small boring minority. It certainly exists though. I once mentioned to a fellow pilot at our small local airfield (I had a part share in an aircraft based there) that I sometimes liked to hang around near the runway at a well-known airport, mainly to judge the quality of the landings, but also to see if anything interesting turned up (which in my case means a DC6 or Lockheed Electra, or something similar)
The response was emphatic: "don't mention that to anyone round here, else they will call you a xxxxxx spotter, or worse"
Sad people. Amazing how some people can fly aircraft while being so disinterested in the larger world of aviation.