Anyhow, the PHB is now $30 on Amazon - that's close enough to your figure, I think.
Yes, Amazon offers some good (even great!) deals. And I may take them up on it. (Or I may buy at my local store to support them.) Or I might not buy at all; I'm currently one of those "On-the-Fencers" I mentioned.

(But imagine the difference between one person buying a book at the SRP of $50, as opposed to 6 people buying at book at the $25 price-tag.)
But mostly my thinking is more about what would benefit the greater audience for 5E?
While I applaud WotC for even putting out a Starter Set (which is, to my mind, a real necessity), I think WotC has burned MANY of their fences over the years, (going back to their cancellations of Dragon and Dungeon magazines and even before!!). and a 3-book-buy in at the SRP of $50 doesn't necessarily help gather new fans. (And yes, I know they say you can play with just the Starter Set, and you can get the Core Books cheaper.)
After an EXHAUSTIVE playtest (which I won't bring into this thread), in addition to all the points from my last post, I think WotC could sorely benefit from some actual postiive press and goodwill that's not just based on their name-branding.
So, why NOT have that reduced price as loss-leader as a "Try This, see if you like it" strategy? (Or even a "If you buy the starter set and like it, take the $20 off the price of the PHB"?)
There's lots of ways to incentivize the gaming audience....