Do we even need that many distributions? What's the value proposition for all those hundreds of Linux distros?

My impression is that for many of them its:

A. we want to make my own distro, to learn, get visibility or maybe even make money

B. we want to make our own distro because of an already existing user base from point A.

C. we want to make our own distro because we can't get along with distro X makers

I wish that the barrier to entry to making a Linux distro was higher. People would have to put more thought and effort into it and the overall quality would be higher.

That is a valid point, and why I usually tell people to just use Ubuntu if they're not sure. The value proposition is that different people are doing different things, and even people doing the same thing sometimes like to do it different ways.

I wish that the barrier to entry to making a Linux distro was higher. People would have to put more thought and effort into it and the overall quality would be higher.

I believe that less competition equals lower quality.

While I generally believe in competition leading to better results for users/customers, the real life experience of Linux distros vs Windows or Mac OS doesn't seem to bode well for the free market :p (i.e. Linux distros should be the pinnacle of software quality and they aren't).

Would RedHat switching to apt make Debian redundant?

yes because Debian (stable) and Kubuntu have different KDE packages

> Would RedHat switching to apt make Debian redundant?

- no because they apply different patches - yes because I think that both Debian and Red Hat and any distro which applies patches is already redundant with Arch

Flatpak is entirely decentralized, anybody can make a custom runtime (Debian/Fedora ones exist), and anybody can host a repository.

If they used the same packages, then there would be a question if they are separate distributions.