The whole expanding to the west argument is flawed in that expanding into another region doesn't equal sacrificing another it would be like if companies back in the late 90s and early 00s ignored US to build themselves up in the PAL region, when they say they want to perform better in the west they mean that they want all regions to perform well for them as market shifts take place every so often and it helps to better withstand them otherwise if a shift happened were western tastes no longer bought into their games as much it would have a big implication on them if they weren't performing well in Japan.
Right now in Japan with PS' performance as a brand we effectively have a near monopoly on the scale almost unseen since the NES days only the platform now holding it also has a monopoly of the portable market which can be leveraged for what's at the moment unchallenged success in the region and an unrivalled dominance of the home market, the problem is a case of the long run as what comes after the Switch is going to be the central issue if this continues which with Sony's approach looks to be the case. It's reasonable to assume that with Nintendo taking their time with a successor which could possibly be 2024 the hardware level of what ever they bring out will have an easier time getting versions of games or even being the lead to be ported to PC like MHR meaning the same developers who are expanding more in the west will still have their games released on it while the smaller developers will just focus on the said platform due to them being more heavily reliant on home sales that's the situation Sony themselves is setting up and it's bizarre that they don't realize.