Two main points:
- no one unified distro to keep things simple (thread OP)
VS
- people don’t care. Someone else needs to advocate, sell, migrate, and support (medium term) Linux (whichever distro they want) for the intermediate term (few months at least) - thread response).
I think a lot of the 97% desktop market share is like this, instead of the hands on 2-3%.
I don’t think “one unified distro”, or even an “official distro”, is possible without taking critical parts of Linux private and closed-source. As long as the freedom exists people will make their own “versions” of (GNU/)Linux.
I think certified distro would go long way. Say this is what it takes to a certified workstation so that people can do basic things using the same tools and guides.
You’re basically describing the Linux Standard Base, which was abandoned back in 2015 and the way it was handled was somewhat controversial.
But there is a lot of informal standardization between Linuxes, nonetheless.