No. Snap started as a project and got useful before flatpak.
Wayland technically was before Mir, but existed as blueprints and ideas back then. Shuttleworth tried to influence its design for his vision of linux desktop, but got rejected, so Mir was created. Mir became useful way before first implementations of Wayland, but Shuttleworth idea to expand Mir and Ubuntu to phones resulted in feature creep, lack of funding and eventually to project failure.
Gnome shell was also released after Unity. Both were influenced by MacOS LaF. The problem with Unity was that it was based on gnome 2 and compiz, that was a good compositor back in the days, but a dead end as a technology, as compositor should’ve been implemented on a lower level and be an integral part of DE. Shuttleworth started Mir and new Unity based on that, but both sank and Ubuntu had to revert to gnome-shell that became useful and more performant than earlier versions.
And GNOME 3 as well? Unity was a reaction to GNOME 3's big changes.
Either way, I agree that competition is better.