In general it seems to me that people place waaaaay to much emphasis on $$$$ when it comes to choosing a career path.
There are lots of people out there who make 6 figure incomes and are miserable because they hate their job. There are also a lot of people out there who make < $40K and are always happy because they love their job. I met a guy just yesterday who turned down a $120K job to keep his $50K job, because he said it didn't sound like much fun, and he loves his current job. The trick is just to live within your means, and not spend like your making $100K when your making $40K. In most parts of the country you can provide for a typical family of 4 quite easily (and set aside a decent retirement fund) on $40K a year.
My advice is to choose a career path you will enjoy, then live within your means at whatever income it provides. Personally I'd rather make $35K a year and be happy, then make $350K and be miserable. In spite of what society would have you believe money is a poor anti-depressant, true being dirt broke and in debt is very depressing, but once you reach the point of being able to comfortably provide the necessities, any money above and beyond that won't automatically make you happier.
So if aviation is what your passionate about, and really want to do, then DO IT! Be happy and don't worry about the $$$$. Remember that nothing is written in stone either, if you want to fly a fun GA job when your young single and don't need that much money, then later settle down, have 8 kids and need to make more money to feed them, great, there is no rule that says you can't switch careers.