It’s lack of being phased out isn’t a matter of laziness, it’s a matter of having better things to do with our time than relearn typing. We have multiple generations that know QWERTY by touch, there’s really no way to phase it out, you either replace it or you keep it, if you replace it then all the old typists need to relearn from scratch, so we keep it.
The way I learned about it, was that the original layout in QWERTY was done to sell, and then, slight changes or tweaks were made, but that overall, it was more for ease of demonstration and selling purposes.
Your right about the multiple generations learning by QWERTY, my view is not to get rid of it, but to simply teach children the DVORAK way instead (they can and still will learn QWERTY on their own, no one is banning anything or making any laws saying no, you can't use this). The younger generations learn it, hopefully keep it (some will, some won't), and in time, eventually, it'll be the more adopted standard. You'd be making the change or transition from the bottom (and dumping cursive while we are at it).
But if you teach the kids DVORAK in the school they won’t have DVORAK keyboards to use away from school, so they’ll learn QWERTY out there, or annoy their parent by figuring out how to reconfigure the family computer to DVORAK. And the big punchline is there really doesn’t seem to be that much gain. I was poking around the google on this and the general consensus seems to be that taking a refresher typing course will increase somebody’s typing speed by about the same as them learning DVORAK and takes less time. It seems that DVORAK is one of those theoretical improvements with little actual improvement. Probably because once people get used to the layout they just go, the more you type the faster you’ll be even if the layout is a little less than perfectly efficient, muscle memory and dexterity seem to have a bigger effect than keyboard efficiency.