[fjtorres]

The issue goes beyond KDP Select (which is only a 180K titles or so).
The reality is that where other vendors run promos (free or non-free) for a few dozen ebooks at a time, Amazon runs promos for a few *hundred* at a time.
And, on *top* of that, they allow/encourage KDP Select participants to run their own promos. (5 Free days over 3 months.)

If you're a bargain-hunter you will at any point in time find a whole lot more deals with Kindle than with the epub crowd. And then you factor in all the *Free Kindle ebooks!* websites picking up eyeballs and clicks by sorting through the freebies and highlighting them and the visibility of the Kindle bargains starts to swamp out the visibility of the competition. (There's money in promoting free Kindle books even if they're not *your* books.)

So, no; B&N (and Kobo and Sony) still run promo discounts.
But not as many people notice or pass the tips on...