Would you like to spend $0 on airfare (only having to pay taxes and occasional fees) for the 5,000 miles/year you do fly?

Very possible.

Only roughly 1/3 of all miles earned overall are from flying. The other 2/3 are earned from other activities.

Spend enough time on flyertalk and most people will easiliy be able to earn 50,000 - 100,000 miles per year doing things you already do. Spend those miles on your flights and never have pay for airfare again.