The number of brand C or P still in service today is largely the result of the marketing policy of each manufacturer. At the time they were built C had 1000+ dealers and probably 800 Cessna Pilot Centers and if you make each of them take 1 aircraft a year then that is 1500+ sold. That is what they did in the mid 60s to kick start the Learn to Fly program and over the years that led to pilots moving up to 172, 182 and then Citations.
Pilots, students and engineers may prefer the Piper but now it is a question of parts availability in the area of operation. I've enjoyed flying both.