What about $130?
That's what the Pathfinder Core Rulebook, Gamemastery Guide, and Bestiary cost, in total -- and what they have cost since their release in 2009-2010. If you assume an equivalent value between the D&D5 PHB and Pathfinder Core Rulebook, thanks to inflation you're actually getting a $5 discount on the PHB.
The Bestiary is as critical to Pathfinder play as the Monster Manual is to D&D. You could argue that the Gamemastery Guide is not as important, but the D&D4 Dungeon Master Guide served a similar purpose -- the PHB contained all the rules needed for play.
This is the first time I've heard anyone describe the Gamemastery Guide as being even vaguely important for playing Pathfinder. I wasn't playing PF when it came out though and might have missed the adds. Was the Gamemastery Guide ever held up at the level of the 4e DMG (which was included in the PF+MM+DMG boxed set, and the 4e PhB says every DM _needs_ a copy of it.)
Did the combined 4E PhB + MM contain the basic mechanical rules for encounter balancing (CR and the like), constructing skill challenges (a major part of 4e GMing as far as I can tell), NPCs, magic items, and magic item construction? I don't remember. If the 4e PhB +MM did, then there are really only two 4e core books in the sense of having what you need to play. (And in that case I'm guessing a lot of the complainers here are remembering earlier editions where you really did need all three, and they would backpedal if 5e did the same thing). If the 4e PhB + MM didn't contain all of those, then, unlike PF, I think it is hard to argue that they contained everything needed for play.
In any case, using the 1st 4E PhB might not be the best way to drum up enthusiasm given that it did not contain several D&Disms - barbarian (3e), bard (2e, 3e), druid (1e, 2e, 3e), monk (1e, 3e), sorcerer (3e), gnome (1e, 2e, 3e), and half-orc (1e, 3e) and you needed to get a second players handbook to get the two of those that had been in every other edition of the game. The 2e, 3e, and PF groups I've played with seem just fine with no splat books. I wonder what percent of those groups thought the splat books/supplements were "necessary" versus the percent of 4e players that thought the 2nd PhB was.
Also, the comparison with PF falls a little flat in that all of the rules needed to play PF (along with all the Advanced and Ultimate books) are available free on-line.
Edit: I agree with your reorganization statement in the post right below this one, but again note the free on-line SRD difference.