In my opinion, there's no one real and good 'model-answer' reason why people give up. Like all hobbies, photography will come and go in life. No time, no money, lost interest, whatever. You may lose interest now, but somewhere down the road you find that life has no meaning, then you realise that, hey, you still have hobbies that you enjoyed in the past. Or a suddent event that spurs your interest (e.g. you found a new girlfriend who looks like Claudia Schiffer - ala "Love Actually")
Photography is an art. Really, it doesn't matter if you use a pro or an idiot camera. Just like drawing, no difference if you use normal foolscap paper and a lousy 2B pencil or an expensive white card-stock drawing paper and soft eraser. If you got the talent and the eye, then you get the picture. One famous fashion photographer (forgot his name) even uses the idiot-proof film camera for his fashion shoots!! How about that!
But it takes more than results to display your worth. Sometimes, you just have to be equipped with the 'right'-looking tools to be credible. It's like a pro tennis player carrying a low-grade racket. Yes it makes him look like a novice, but bet you he will beat the real novices in all games even if they carry pro-rackets. In the case of photograhy, would you trust a person to photograph your wedding with a compact camera (no matter how credible he is), or you'd rather go for the one who has a DSLR?
On the other hand, one shouldn't get a pro-cam just for the namesake. Photography, like all hobbies, should grow with you. Start with basic equipment, and when you find that you needed more features and control, then upgrade to the next level. One guy I knew just started digital photography and he bought a Minolta A1. 2 weeks later, he sold it, and got back to his film SLR. He's still in a dilemna about converting to pro (maybe tha A1 overwhelmed him). My advise is: get a good compact digicam (like Canon S50) and move on from there.
