Let me give you some examples of miles value
Look at the details on this one. Biz Class award to Madras for friend
-120k miles - 235$ taxes = 3240$ + 30k miles (20k travel + 10k Biz bonus if paid ticket)
Add 120k miles each => -235$ = -3235$+150k miles
Add 3235$ each => 3000$ = 150k miles
= 2 cpm value out of 1.5 cpm cost = 0.5 cpm free money.
Real out of pocket cost = 1.5 cpm anyway to get a mile or point. (miles bought in March)
For the economy ticket, it is a slightly different equation.
-80k miles - 150$ = - 1350$ +20k miles
Add 80k miles to each side => -150$ = -1350$ + 100k miles
Add 1350$ => 1200$ = 100 k miles.
Or, you get 1.2c of value for each mile, which itself has an opportunity cost of 1.5 cpm.
Can you rewrite this to clarify your point? I think you're factoring in the loss of earned miles when using an award ticket -- but I'm not certain. If so, you need to factor in the value of forgone EQM's, too (not just the value of forgone miles). But I'm not sure how to value EQM's vs. regular miles.
To further complicate things, keep in mind that many of us would NEVER actually pay for a C or F ticket overseas. Take my itinerary to HKG in F, which would cost $22,500. I would never actually pay for that itinerary, so the most miles that I would truly forego by flying on an award ticket to HKG is the mileage I'd earn in Y. The F bonus cannot be factored in since I would never buy that itinerary in F.