It's some work to keep track of all the promos, and if you're finances or credit do not allow the spending or the numerous credit card applications, then yes, you're at somewhat of a disadvantage in this game. Those opportunities, however, eventually do come, especially as you earn more money and become more credit worthy.

Thanks for your elaborate and thoughtful reply.
My problem is not that I don't earn enough money (I made 76k last year), or that my credit isn't up to par (my score is over 800), it's that I am quite frugal, and I just don't consume as much as the typical American does. Instead, I invest my my money (over 42k/yr). Now, if I could earn miles for every dollar I invest, I would be in Business Class in no time!