there's a lot of reasons for individuals when they give up something, no time, money, lost of interest, priority changed... etc etc. but i think sometimes some of them just want to take a break after all the shooting and stuff, it may be that their creative juice is out and they need to step down to recharge or something. some people bounce back with greater achievement than before.
i think that having very good equiptments is a very good bonus, when one is able to afford them and use them to the fullest, but some low end P&S equipments can produce very nice pictures also, i think it depends on the user, whether they wanna push what they have to get something better. IMHO, it's important that the owner know their cam well, so that maybe they can do amazing thing.
just my opinion. hehe..