I don't think we're quite at anarchy levels yet

Fewer repositories would be better. But, I would think that having some outside repositories would be a good thing. For instance, I think with a little digging, I can find a sizeable package to install cups printing support. Put that in extras (or even extras-development) and I bet there'd be dozens and dozens of requests for "help printing" or "I installed the printing package, why can't I print anything" or "how do I get xxx printer setup to work", etc, etc.

Most users will at least understand that if something is in an outside repository, there is less likely going to be good support and/or problems.

Of course there will always be people that will click on anything that says install, even if it says installing this will render your device useless. I suspect that if it were easier to install multiple items at one time, there'd be dozens of people complaining that "I installed everything down to g... and it crashed, what happened?"