As far as I could tell from everything I've read from multiple sources, every Pixel since Pixel 4 _has_ the chip, it's just not enabled and you can enable it with rooting.

https://xdaforums.com/t/global-pixel-device-unlock-felica-su...

The chip is not missing, the configuration is.

I assume it's a licensing issue, where Google is too cheap to pay JR for the phones sold outside of Japan, so only setup the JP models and only pay the license for those.

No, the chip is there, gated by a SKU check, so that Google only pays the licensing fees for their Japanese SKU.