No, I would not have ever paid cash for this F trip, but I think this is fun to look at.

I used 145,000 miles and ~$165 in taxes for a nearly $20K trip in F:

IAD-FRA-ZRH-BKK-CDG-FRA-IAD with LH, LX, TG, and UA.

That was the price given when I forced the exact routing of the award tickect. Could get to BKK in F for quite a bit less, I'm sure.