I think the empirical evidence is against you here, though. If package managers weren't a good way to do things, brew wouldn't exist. Neither would the Mac app store, or whatever the equivalent on Windows is these days.

As a Debian user, I appreciate that the stuff I install had at least gone through some minimal vetting first. And if I have to add a third party repository or download something myself to run, I'm much more likely to view that as the possibly-dangerous action that it is, and try to actively assess the reputation and trustworthiness of what I'm installing.

That's certainly not an average, noon-technical user thing, though. Vetted app stores are there to help average users avoid malware, assuming they're doing their job properly.