I'd say this is due to
- disagreements/factions
- wanting the satisfaction and validation of building something yourself
- implementational conflict with existing systems
Sometimes the validation thing is due to ego, sometimes it's because the journey of building a new system is useful in itself.
In the case of the distro I want to create (:P) it's because the (very simple) ideas I have conflict with the way things are commonly done, so I'm going to have to set out on my own. It'll be fun though. Users in my case will be a headache because then it won't be a fun personal project. I just want to solve my own frustrations.
And "Linux on the desktop" has been a meme for years. It'll never happen until Linux achieves cohesiveness, aka never, full-stop. (Took Microsoft a while to figure that and build WSL...)
NB, I don't see an email or other contact details in your bio. I could let you know when I finally do get around to starting w/ that distro.