The basic problem there is that no company in the industry, from Apple all the way to the lowliest gray box manufacturer in China is not interested in that.
OLPC tried, it got hoodwinked by Microsoft et al.
Mozilla tried, FirefoxOS bombed.
Hell even Linux is turning ever more complex an opaque year by year.
Simple thing is that such flexibility self support do not sell widgets and support contracts, and thus company are not interested in making them.
Well, yeah. For the benefits to be realized you need a society that values that sort of thing. It will look quite a bit different from our society, just like societies with writing are completely different from entirely oral societies -- something else Kay touches on.
OLPC and Firefox OS are not examples of projects that pushed the idea of an OS and application stack that could be understood by a single person. To get a better idea of what Alan Kay has been working towards I'd recommend checking out the STEPS project.
The software for both OLPC and Firefox OS were both based on Linux. Is there anything that made them more approachable on the low level than any other Linux distro?
I say that they were the closest, not that they were complete implementations of the vision.
Firefox OS had a particularly hackable UI layer. You could install webpages as if they were apps (all assets stored locally), bypassing the need to get your app into a curated store. Writing new drivers in Javascript could have come later.
OLPC tried, it got hoodwinked by Microsoft et al.
Mozilla tried, FirefoxOS bombed.
Hell even Linux is turning ever more complex an opaque year by year.
Simple thing is that such flexibility self support do not sell widgets and support contracts, and thus company are not interested in making them.