That's the world some have built. There are other approaches to this such as the apple store and linux repositories, they contain trusted software with various

That's the world some have built. There are other approaches to this such as the apple store and linux repositories, they contain trusted software with various degrees of vetting and it's extremely rare to have to install something I don't trust, sand boxing is a good idea for those apps though. A huge problem in software is that the trade off for security is almost always usability and/or convenience.