I was pleasantly surprised that my Prime subscription might actually still be useful for something.
Subtitles would help a lot but even that is missing with a lot of providers (I wonder what people with hearing disabilities do).
A far worse offender, for me at least, are Blu-Rays in that regard. During their introduction, they were hailed as allowing distributors to pack dozens of high-quality different language tracks and different subtitle options on the disc.
While the reality these days looks like this: Most Blu-Ray releases are still regionalized, very often with limited audio language options (in 2.0 quality) and sometimes not even subtitle support for one language.
I think a lot of that has to do with distributors pretty much forming cartels by region, thus having only rights to distribute only specific versions in specific regions.