If you remember correctly, they did have a few special discounts and deals but they were very selective and prohibitively in short supply. For example, the newegg deal with the 329$ ps4 that sold like 20k, among other special limited deals.
Business wise, lowering price across the board would have increased demand more than the supply they could produce. Sure a few hundred thousand weren't sold because of that, but they made the money up front, instead of relying on ps+ or games to recover the costs.
ie; Yes, it cost them some marketshare and install base, but it made them more money up front. 50$ non price cut is 50$ saved, which is better than 10-15$ on a per game basis. And then you look at order barely a month away...and then bloodborne.
Just in the grand scheme of things, it made more sense to not have a sale. I hope I didn't flesh it out too much, but that's how it is. I'm surprised there are even questions about this.
The simple answer was in the second post of the thread. 'Sony would win without lifting a finger.'