so if you buy one then decide a while later its not for you, you'll most likely get a 100% return on your investment.
Just to be a pain about the language for a second: a "100% return on investment" means you double your money. I think Luxor meant a "100% return of investment," meaning you get all your money back when you sell...which certainly might be true if you buy used and get a good deal. I do think that it's a fair point that pump markers, especially those bought on the used market, don't depreciate as quickly as many of the more popular semis. The availabilities and lead times are such that prices stay high. I'm thinking of the CCM pumps...good luck finding one in good condition for a lot less than retail.
Not a single product will retain its original retail value, paintball markers of any kind are no different in this regard. And also. There are companies making new pump marker model in this day and age..
Like any other niche market, paintball equipment can be funny. The mass-market stuff will surely depreciate. Low volume, build-to-order guns like CCMs and Phantoms won't depreciate as much. And then there are weird situations like Sandanas and Winchester Pocket Hoppers where the prices go nuts.