It's likely the same problem as in Pakistan. Due to the history of colonialism/control by European powers, in these countries personal economic success is usually tied to command of English or French. So even within each of these countries, the rich, educated and those in power prefer latin script. Consequently, there was never any strong push to develop computing technology for local languages.

The other reason is that it's not technologically simple to solve all the issues highlighted in the TFA. Unicode actually does a pretty decent job of setting a uniform standard, but a lot of software has to be written on top of it to get the entire system working: (1) your software must support bidi text, (2) good fonts must be available to display the text in multiple languages (3) textual data needs to be properly stored in unicode and transmitted as is at every point in the OS (4) search engines must deal with the complications of non-breaking spaces and legacy unicode characters.

You have to kind of rewrite the entire stack from top to bottom. Preferential Arabic/Persian/Urdu speakers never had the technical skills and the political power to drive those changes in software largely written in different continents.