classic question...
in my opinion, most people pursue replicas because they can't afford the real watch. we all know many of these people who wear the watch to pass it off as something that it is not. this is unfortunate because as a fan of haute horology - as many have mentioned in this thread and all over the rwg site - replicas (from basic rep's to super reps to franken's to whatever) are exciting and lot of fun. i own a few gens and a few replicas and i enjoy them tremendously from the aspect of watchmaking and aesthetics.
rationally, i believe you can explain most behaviour with simple economics. the opportunity cost and inherent value of any gen is ridiculous. there is no reason to purchase a gen patek; the incremental gain of enjoyment of the gen versus a replica is nonsensical (please note that the exception is people who sell or trade watches for a living as this would then be derivative on market forces for value just like diamonds where a real diamond has a market value of x and a zirconium diamond has a value of y).
the interesting aspect is that, at the end of the day, we are many parts irrational and the ultimate answer and choice is probably some amalgam reflection of personal mores and desires one ascribes to.