Let's put it this way:
When I was younger, I really wanted to play in the NHL. I LOVE hockey... I play hockey, I watch hockey, I read about hockey, I work out for hockey, I play hockey video games. Even to this day, I go to an NHL game and think, "Wow, it'd be so cool to play on a big stage like this." However, in reality, I probably wouldn't want to deal with everything that comes with being a pro hockey player. Lots of travel, training, gym time, strict nutrition, practices, injuries, etc.. Right now, if I want to play hockey, I pay my $10 and go play. If I'm not feeling up to it, I stay home and play hockey online. If I was in the NHL, I wouldn't have that luxury. I'd need to be at practice on time, at the game on time, even if I didn't want to skate that day. Although, I would be getting paid lots of money to play hockey, which is definitely a plus!
The same could be said for flying. Some people are willing to make the sacrifices to get paid to fly. They don't have to shell out their own money to rent a plane. Plus, if you make it to the big time, you can make a very good living. However, you have to realize that there will be days you don't want to fly, but you can't say, "eh, I'll stay home today and play Ace Combat 6 instead." Also, just like the NHL, some will make it to the "show," while others may not. Often, it's not even dependent on skill, but rather timing and luck. There have been many, many pro hockey players who made their careers in the minors. Same can be said for pilots in the regionals. There are just too many pilots... and too many hockey players... trying to get into a position with limited spaces available.