I don't agree. There was a FOSDEM talk by one of my colleagues specifically about this issue, and why Flatpak is walking us backwards in terms of how packaging has worked historically[1]. Distributions are far from perfect (hell, some of them ship my packages and I'm definitely far from perfect) but they do solve real problems and going to a Windows-DLL-dump method of packaging is going in reverse.
If your "package format" makes developers maintain all of their dependencies, it isn't solving the problem that most people actually want you to solve -- to be able to do less work and build on top of other people's work. By using dependencies maintained by your distribution you also get security updates and maintenance for free -- many distributions have paid security and maintenance teams that deal with precisely this. I cannot overstate how much work it is to maintain your own distribution.
