Comment by mustermannBB

I think it is way simpler than that. IMHO, for many people young or old the value proposition of emacs simple is no longer there and/or worth the huge learning curve. For most things people would use something like emacs the alternatives are simple good enough and some cases better. By better I mean mostly more accessible, less complex and with a better ecosystem. One tool that does all, also simply does not resonate with everyone nor do many people feel the need to make their almost their lifestyle (not saying you do, I'm speaking in general to the Emacs runs my life folks). Another thing to consider often is that when working in a group or team at work for example it can be the easiest path forward to use the tool the company officially uses and your teammates do. If your team uses for example slack to communicate why go through the hassle of setting up some most likely cumbersome workaround to target it via emacs instead of just using the slack.