TL;DR I tried to prepare a composer.json file that would install Mautic in the the vendor foler. That wasn't the hard part. I got stuck on making Mautic work that way.
Using Composer to install PHP packages is great. Why shouldn't we install Mautic this way? I wanted to make it work mainly because...
I wrote in my previous post about Mautic 3 that the Marketplace is the greatest weakness of Mautic today. Go to that paragraph and read what I mean by Marketplace so we are all on the same page.
At mautic.org there already is a section called Marketplace but that's not what I consider a market...