Why in filenames and folders, some characters are not yet accepted?

Why don't files and folders still accept a few different characters?

I believe it must have some programmatic influence to have made that decision. Did Operating Systems have and / or still have restrictions for them to be produced this way?

As well as domain names that previously did not accept accentuation and different characters, and have been working with them, more recently.

An Internationalised Domain Name is a domain name that can contain characters not defined by the ASCII standard. These characters include most of the accented letters used in different European languages and other characters that are not found in the Latin alphabet. (i. e accentués.com)

Technically, accented characters can not be used in DNS, which is why every IDN is encoded as a string of non-accented character whose shape is called ACE. In the latter, the domain names begin with XN-to differentiate unaccented domain names. (i.e. : xn--accentus-h1a.com)

(excerpt from here )

Example:

The domain name ¥ƒΩ converted into ACE chain is xn--cba88bf7c

In this Article from w3 talks a little about this "internationalization" of{[1 domains]}

User's expectations and use of the Internet have moved on since then, and there is now a growing need to enable use of characters from any language in Web addresses. A Web address in your own language and alphabet is easier to create, memorize, transcribe, interpreter, guess, and relate to. It is also important for brand recognition. This, in turn, is better for business, better for finding things, and better for communicating. In short, better for the Web.

I believe that this question is more about the history of creation (so it has a little to do with programming) of systems operational.