There seems to be several factors involved in the lack of price cuts. The PS2 started at $300 and got down to $99 eventually. The PS3 started at $500/$600 and eventually got down to $270/$300. So the PS2 ended up at 1/3 of its launch price, but the PS3 was closer to 1/2. And now the PS4 is only 3/4 of its launch price. Who knows if it will get another price cut? It seems like the big 3 don't want to drop the price like they used to.
But adding to this, I don't think PS4 had much competition during Generation 8. The Wii U and XB1 basically failed on their own, so Sony didn't have much incentive to drop the PS4 price. It kept selling well at $300 and what else are you going to buy? PS4 was clearly the best option. In Generation 7, the systems were a lot more compeitive with each other.
And now there is the Switch. They can't keep enough stock on the shelves right now, so there is no way that Nintendo is going to drop the price. So, at the moment there doesn't seem to be a lot of incentive for companies to drop the price. The best people can get is some sort of holiday deal.