Emacs doesn't just work out of the box. Nobody has time to fool around with Emacs and learn a bunch of non-standard shortcuts. Just to do what you're suggesting it would probably require installing an entire package manager within emacs, then using that package manager to install some packages, and installing whatever packages outside of emacs, and maybe you'd even have to put some lines in your .emacs file, and probably even more steps. There's a 100% chance there will be some issue along the way. Emacs is an archaic dinosaur. It has a high barrier to entry. Nobody uses it except computer programmers. Many graduate students can't even be bothered to install TeXMaker. A lot of them use Overleaf just because it's the path of least resistance.