This isn't necessarily true - a developer choosing to not include their app in a repo can always opt for a self-updating mechanism.

Don't get me wrong - repos and tooling to manage all of your apps at once are preferred. But if a developer or user wants to avoid the Canonical controlled repo, I'm just pointing out there are technically ways to do that.

If you'd question why someone would use snap at all at that point… that would be a good question. The point is just that they can, if they want to.