I agree that users want things to be simple. That still does not necessarily mean that Moodle should build everything. A good example of this is Linux. If you buy a laptop, or a server, running 'Linux' then actually what you are probably buying is some distribution like Redhat or Ubuntu comprising the Linux kernel, and numerous applications created by other projects. The distribution, which brings together all the different parts, is yet another project.
The point is that all these different projects are doing different kinds of work. The kind of things required to build the Linux kernel, or Libre office, or package it up for users, are all different type of software engineering, so it makes sense for them to be done by different groups of people. Now, a web-based VLE, and a web-based SIS are more similar than the Linux kernel and Libre office, but are they more similar that Libre office and GIMP?
At the moment, the only people packaging Moodle with other things (e.g. ELIS, Totara and Joule) are at the more commercial end of the Moodle community, so their work is not fully shared. But then in the Linux world, the earlier distros were more commercial, and the more open ones came later. I think. Actually, Debian has been around for a long time. I might be wrong.