I don't think that's true. Both Latex and C++ were replaced. It's just that their best replacements were more specialized tools so that left a bit of space for

I don't think that's true. Both Latex and C++ were replaced. It's just that their best replacements were more specialized tools so that left a bit of space for both to survive. It's just like that example of cars mostly replacing trucks in the US. Trucks aren't obsolete, but most don't need them so choose alternatives that fit their life better. Latex was replaced by Microsoft Word, Adobe InDesign, and Markdown. Each one is different but for people who might have used Latex for a certain use case, one of those more specialized tools might be better. But there will always be a need for Latex itself.