Well the problem of Snaps is complex sandbox, lack of user control, forced updates and so on which is disliked on many non-Ubuntu distributions.
Flatpack attempts to solve the dependency hell problem by providing standard runtime, a set of libraries, Glib-C, Gtk or Qt with a fixed version which requires the developer to build an application linking against those runtime, which avoid binary compatibility problems and dependency hell. The trouble of Flatpacks is the integration with the desktop.
AppImage attempts to solve the dependency hell by bundling everything into a single launcher executable with a SquashFs file system image payload. The disadvantage of this approach is that it is only possible to use a single executable. AppImage are also not free from GlibC compatibility issues.
A MacOSx-like app bundle and a changing in Linux development culture to build and design applications as self-contained from inception would strength the Linux desktop and reduce the application packaging work duplication that still affects Linux distributions.
Flatpack attempts to solve the dependency hell problem by providing standard runtime, a set of libraries, Glib-C, Gtk or Qt with a fixed version which requires the developer to build an application linking against those runtime, which avoid binary compatibility problems and dependency hell. The trouble of Flatpacks is the integration with the desktop.
AppImage attempts to solve the dependency hell by bundling everything into a single launcher executable with a SquashFs file system image payload. The disadvantage of this approach is that it is only possible to use a single executable. AppImage are also not free from GlibC compatibility issues.
A MacOSx-like app bundle and a changing in Linux development culture to build and design applications as self-contained from inception would strength the Linux desktop and reduce the application packaging work duplication that still affects Linux distributions.