This doesn’t solve the problem either, which is that of the Confused Deputy [1]. An arbitrary piece of code I’m downloading shouldn’t be able to run as Ryan by default with access to everything Ryan has.
We need to revitalize research into capabilities-based security on consumer OSs, which AFAIK is the only thing that solves this problem. (Web browsers - literally user “agents” - solve this problem with capabilities too: webapps get explicit access to resources, no ambient authority to files, etc.)
Solving this problem will only become more pressing as we have more agents acting on our behalf.