your reason 7 is actually one of the biggest reasons people won’t. Too many options just confuses and frustrates people.
99% of the people out there can do just fine...better than fine...running Mint, Ubuntu, or Fedora.
Unless you are doing console work, you really won't notice that much of a difference between the three (except that Ubuntu has these really annoying sounds in the default theme). More importantly, from the GUI, if you can run one of them, you can run any of those three.
For those with different needs or different hardware, that's when you need to start playing around with other distros...for example, Peppermint (as I mentioned above). Again, though, from the User POV, there really isn't all that much of a difference in how they run...unless you start going to the console level.
Personally, I think that Linux users are the biggest impediment to more widespread Linux use by consumers. (Try going on a Linux forum and either asking a question that's already been asked...even if it was asked 10 years ago...you'll likely get a smart-aleck "search is your friend" answer. Alternatively, you'll get 50 lines of code to input. While that works just fine for those who aren't intimidated by it, grandma may want a point-and-click solution so she can send an email to Betty)