[MKDremare]

That new map thing that they have in their Tamashii Web product pages now shows the regions they sell products in (haven't actually really looked into it), and they divided it into Japan (self-explanatory), US (also self-explanatory), Asia (China, Korea, most of Southeast Asia, and Australia), EU (Europe, South Africa, and some tiny bit of Saudi Arabia), and LATM+ (Canada, Mexico, Chile, and Brazil). It's not actually worldwide, considering that most of Africa, West and South Asia, and Russia are omitted.

But back to Kamen Rider, yea it's big in Asian countries, but in the West it's really not. It's still really niche compared to Toei's and Bandai's other big properties, so it's not unexpected that they're not immediately putting up KR P-Bandai exclusives on the US Tamashii Web store.