Miles for tax payments? That's so last year.

In years past, the run-up to tax day has seen a predictable surge in individuals looking to earn frequent flyer miles for tax payments.
This year, that interest in conspicuously absent.
Taxpayers can use a rewards credit card to charge their payments through
Official Payments
or
LINK2GOV
, and thereby earn miles for their taxes, just as they would for any other purchase charged to the card. But there's a hitch: consumers pay a 2.49% "convenience fee" for any payments made through the two intermediary companies. And that seriously erodes the value proposition.
In any case, I haven't received a single reader question this year about the mechanics or desirability of this earning tactic. Nor have I seen a single media story about it. And the question arises: Why?
Is it because consumers are generally less engaged with loyalty programs? Have program members done the math and determined that the fee is a deal-breaker?
These are not rhetorical questions, incidentally. I truly don't know what's at play here. But when I know, or have a theory, you'll read about it here first.