Came from the same realm as you did Quattro. Did some rounds in CXBL and MXL for a few years. Before that was OPPL and TOC for a number of years.
To me its a difference in between competition and hobby/fun. I came to airsoft to relax, and have a slower and less competitive games. But I never gave up pb. To me they're two different elements. Sure they both use "guns" but its just different for me. They're both fun in their own ways.
And yes cost wise, airsoft is about 1/2 to 2/3 the cost of pb. I'm used to dishing out 1G+ for markers (DM's and MacDev's), so it is a welcome change to get into airsoft and see cheaper pricing.
I'll never give up either, but to each their own as they both have their merits.