They're not going to do that. GPL forbids it.
I don't think there is anything to stop you providing an original install kit for something like Python as long as you don't modify it or pretend you own it. Just deliver it as is and provide attribution of the source as appropriate.
Yeah it kind of depends on who you're asking. Richard Stallman would say that you'd burn in hell if you dare to mix drinks. Actually he says you shouldn't use any code that does not have accompanying source but that's another issue.
I don't know why it is but OSS (open source software) normally does have the fragmentation issue for numerous reasons. The goal of a project coder is for a software package to do one thing and do one thing well. The trick is to get it to couple with other software without breaking this tenant.
Packagers on the other hand have the laborious task of putting all this together, testing and juggling various licences among packages and serving up the "one click" solution that proprietary software users are used to.
Instead of the one click solution, what is needed is a separate tool that checks for correctly installed pieces, tests each one and reports what is missing. That would have hilighted the junk software that Dave had to reinstall (!) and saved all that custard chucking.
edit: I wanted "separate". I typed "seperte" and the browser spell checker suggested "perverter"