You make the same mistake as the NYT - equate FFPs with credit card earnings. There are people out there who earn those miles by actually flying and if those flights are paid by someone else, their cost price is zero. Same with hotel points - earning them while actually staying in hotels on someone else's dime. So my proposition of zero cost vs any cash benefit is valid. Of course being human we try to milk as much benefit as possible but if the supply is close to unlimited, it tends not to matter.
My example - earning 50k+ miles monthly by flying makes the redemption "value" irrelevant. Should I spend 100€ on a short hop or 20k points? Real no brainer.

When it comes to credit cards, your (and the NYT's) analysis does have merits, of course - the main argument being that cashback can be used for anything, not just hotels (or flights)