PS4 has had two price drops in the US. In late 2015, it received a $50 price cut (price reduced to $349) and with the introduction of PS4 Slim the price was further dropped to $299. In addition, the non-permanenet deals (such as the $200 Slim during November of 2017; $250 Star Wars bundle of December of 2017) all helped to substantially increase sales for the system in those respective periods.
As for Japan, it is true that the last official major price cut for the stand alone system was in 2015 which reduced the price to ¥34,000. However, since the Switch launch most retailers (at least online going by Bic, Amazon, and Yodobashi) have been selling the PS4 at the RRP for the Switch (¥32,378), with some retailers (namely Amazon) going lower. For example, the Amazon listing you posted has the price at ¥34,000, but upon clicking the listing, the actual price is listed as ¥ 30,895 which was already down from ¥32,378 (which is odd considering the system is out of stock).
I guess that Last of Us bundle is so expensive because it's rare these days, or something. The listings I saw were mainly for used models, and that was the only new unit I found. But upon searching further I found a PS4 with a bundled game for $350, so you're right.
As for Japan, yeah I saw that they have a deal on PS4 that's a bit lower, but the RRP is still there, just strickened through.
Pretty odd that they've only had one price drop in Japan, and two in the US.
The first price cut in both Japan and US coincided with each other, so it is odd nothing happened in Japan with regards to the price in Japan with the launch of the Slim.
Although the strangest thing by far in Japan is why retailers are selling PS4 below RRP when the system is currently supply constrained. Typically, retailers sell above RRP when demand is higher than supply. My only guess is that the retailers are competing with each other for orders.