What you say is true, But only for those without disiplin. I made my first site just to make money and it was about loans and credit cards,I am no expert let me tell you that.I made 2k in 3 months then later on sold the site for $3,500. now I am making sites every 3 or so months some I am interested in and others that are just really easy niches to target. I make a fair enough living off the net now and it's because I just put hard work into it, like most jobs its a real pain in the arse but I get to spend more time with the kids and work less hours than what I did in my old job.. Money = hard work + disiplin + a little brains. yes your sites will be more of a success if you have interest in them but not all the time..
I would tend to agree completely with OP. It is no denying the fact that with or without inherent interest, people can make money... But the moot point is...is the whole exercise really worth it? Why not make the journey itself more interesting by choosing to travel the path more dearer to your heart. I know earning money is very important, but it is also equally important to enjoy the process of going about it. Regards, RightMan