I think you're actually agreeing with me here. I was disputing the claim that software should be made available in "a native package format", and my counterpoint is that devs shouldn't be packaging things for distros, and instead providing source code with build instructions, alongside whatever builds they can comfortably provide - primarily flatpak and appimage, in my example.
I don't use flatpak, and I prefer to use packages with my distro's package manager, but I definitely can't expect every package to be available in that format. Flatpak and appimage, to my knowledge, are designed to be distro-agnostic and easily distributed by the software developer, so they're probably the best options - flatpak better for long-term use, appimage usable for quickly trying out software or one-off utilities.
As for tar.gz, these days software tends to be made available on GitHub and similar platforms, where you can fetch the source from git by commit, and releases also have autogenerated source downloads. Makefiles/automake isn't a reasonable expectation these days, with a plethora of languages and build toolchains, but good, clear instructions are definitely something to include.