Sure, some of it is that iPhones (Pixels) do a good enough job for a lot of us. But it's also that the gap has closed so much and a lot of it is about software.
Go to events in Japan and a lot of the design of posters and so forth just looks seriously bad to US (and presumably European) eyes.
And even in the large systems space, when I was an IT industry analyst, there was just a lot of quirky Japanese tech stuff that was out of step with the world as a whole.
I don't have a coherent theory for it all but Japan just fell out of alignment with mainstream patterns especially in the 90s or so.