I didn't claim that it's better to pay $18k.Since he claims it is better to pay 18k then I have sure he must have methods to get that 18k from the same spending. Please share how to buy "unlimited" miles at much lower than 2c per mile, I am trying to get more miles and 2c seem to be the barrier.
What @fr33d0m said is right. The extra tradeoff for redeeming award tickets with miles is having to spend time and effort hunting for availability — maybe it's better to calculate how much your hourly rate is, and whether you are interested enough in award redemption to learn the various redemption tricks to squeeze better value out of your miles.
I noticed that you used 372k for 3 tickets, so I guess you were lucky enough to find Saver tickets? But what if Saver tickets weren't available?
No amount of miles can get you SQ business class tickets to most places in Europe this/next month. (Then again, I just took a look at revenue tickets and many dates in the coming weeks are also sold out of revenue seats.)