It absolutely is the property of technology. You fundamentally need the see-through layer, and there's not a lot of materials that meet all requirements (optical transparency, durability, finish, coatings, etc); essentially it's plastics and glasses. In that sense, EPD isn't any different from other display tech.

E-inks do not require a glass screen; it's there for durability. See https://www.digikey.com/en/maker/blogs/2022/is-an-e-ink-disp....

Thus, the see-through layer is not a fundamental property of the technology; it is a property of the specific use cases of the device in which durability is required or expected.

Why would EPD be different from LCD natively shipped with anti-glare coating, or selected good matte films for our glass-based displays (e.g. "smartphones")?

It isn't, that's my point. Both fundamentally have the same issues with glare, contrary to the OP claim that EPD is somehow glare-free. It can be mitigated a bit but getting to the glare level of actual paper (essentially zero) is probably not possible without major tradeoffs.

Ok - yes, you said that literally on your original - but then you interpreted as "property of technology" the parallel issue I was proposing.

What I intended to propose was, there may be unexpected glare issue with EPD display instances: you buy an LCD monitor and make sure that the matte coating is satisfactory; you buy a pocket computer and have a selected matte film applied to it; you buy an EPD display and go "it should be more anti-glare".

I said that this is inherent to the outmost layer that the producer chose for the product. To be that glare susceptible is not inherent in EPD as a technology. The product could be shipped at the quality level of good matte products or good matte films, or you could probably fix it with the best matte film available as you do with displays with front glass.

A good matte display (via coating in-factory or via film aftermarket) is not as glare free as paper, but it can come pretty close.