It's not just website language localization. It's having customer service that actually speaks the language. That's not impossible (Netherlands-based Booking.co

It's not just website language localization. It's having customer service that actually speaks the language. That's not impossible (Netherlands-based Booking.com supports a ton of different language), but online retail is a low margin business, and for most multinational businesses it is simpler to let the locals deal with the retail aspect. It works for Philips and Bosch, after all. You can get away without offering this for some types of products and services, but remember that you are competing with local vendors who do. And yes, of course, there are other issues, such as shipping overhead (for anything that involves physical products) and payment method preferences. But language on its own is already a significant obstacle towards exploiting economies of scale beyond the national level.