You can update as often as you like, but that does not ensure users will get that update, nor does traditional packaging make it safe to install the update (no rollbacks, maintainer scripts run as root and have full access to the filesystem, library mismatches, etc).
I'm all for debs and rpms, but they seem best suited to providing the base system.
[disclaimer: I'm on the Snapcraft team]
Package managers don't prevent this at all. If you host the repository then you can update as often as you'd like. Some whole distros (arch) do just this.