Although I can understand what you are saying, and I would not put it at all like the OP did, I don't think it is necessarily paranoid. For example, almost every single piece of software on my laptop is open source and either built by me, or a 3rd party I trust that didn't write the software in the first place. The packages I install are even signed by that trusted 3rd party. This is one of the reasons why my laptop is more secure than a laptop where more than half of the software is auto-updated, obfuscated binaries built by the people who wrote the software.

Certainly not everyone will do this. Although it is probably no longer considered part of the maniac fringe, I don't think it's going to be mainstream any time soon. However, the benefits are not imaginary.