they’re doing a disservice to themselves by simplifying their logos to plain text.

It also dilutes their branding when translated into different languages/writing scripts.

That McDonald’s ‘M’ is instantly recognizable in every language, even languages that don’t use Latin-derived letters.

But if your logo is plain text, how do you translate it into Cyrillic or Kanji? You either have to develop a completely new logo for those regions (hurting your worldwide recognizability) or you just roll with the English logo and have to deal with most of the locals seeing it as completely unintelligible.