The price is fine. It's supposed to be the Lexus in the line-up, not the Toyota. It's for those who don't mind paying a "premium price" for a luxury product. It was never intended to out-sell the base model.
Honestly, if they just made another console at the same level as the PS4 Pro, it would be an empty gesture. No one would leave the Playstation ecosystem for a side-grade. With this, though, they might pull away a few gamers who value resolution and "power" above everything else.