It gets tried every so often, but there are HUGE differences between companies and geographical/political governance.   

The primary difference, in my mind, is filtering and voluntary association.  People choose where to work, and companies choose who works for them, independently (mostly) of where they live, what kind of lifestyle they like, whether they have children or relatives nearby, etc.  Cities and countries can sometimes turn away some immigrants, but they universally accept children born there and they can't fire citizens who aren't productive.

What you want sounds like Próspera. It is too early to say how that will work out.

They took some inspiration from Singapore. When Singapore became independent in 1965, it was a poverty-stricken third world place. It now has a better GDP/capita than countries like the USA. And also did things like come up with the best way of teaching math to elementary school students.

But Singapore is only libertarian in some ways. They are also a dictatorship who does not believe in, for instance, free speech. Their point is that when you cram immigrants from many cultures together, you'll get problems if you don't limit how much one group is allowed to offend another. I don't like it, but also don't have evidence that they are wrong.

And finally, most utopian experiments don't work out very well. See A Libertarian Walks Into a Bear for an amusing example.

My model says that a lot of the changing occurs by gradient descent, which can be interrupted randomly without causing problems. And there's enough redundancy that the reorganization part can be interrupted without the core information being removed completely from the brain, and the redundancy will be replenished (one of copies I imagine is "locked" while the reorganization happens, and is later reorganized later with another copy "locked"). I also expect this replenishing can happen during awakeness, though not as ideally as when asleep.

But I will also note that forgetting is a thing that happens, which is indistinguishable from "data corruption". We're actually quite good at forgetting things.

If the observation contradicts the assumption, perhaps the assumption is wrong.

Great, if works flawlessly. Impossible to debug otherwise.

(I prefer to use applications in English even if localization is available, because if they print an error, it is much easier to find an advice online. With user-tailored user interface, asking anyone else anything would become impossible. You would have to hope that the AI will explain what happened. Or maybe the AI under guidance of a human experienced with this kind of debugging.)

On the other hand, I like this idea. Unifying all applications that I already use would be awesome. Classifying the messages according to their importance from my perspective, even better.

But I doubt that this future will come. Remember that the most powerful IT company today, Google, is an advertising company first and IT company second. It is definitely not in their interest to make the AI too friendly. No matter what you want, you will get your daily dose (defined as: as much as possible) of advertising first.

"Do you really want to live in a world without Coca Cola?"
I don't really care about sports, but I imagine better athletes must be more entertaining to watch for people who do care. Even if you were to work in an important problem, you wouldn't do it alone. You would probably be one more person contributing to it among many. So you can also look at each celebrity as one more person working at the problem of creating entertainment. Imagine if all music were wiped out of the world by magic. Wouldn't that suck?

The VAST majority of matter and energy in the universe is in the non-purpose category - it often has activity and reaction, and effects over time, but it doesn't strategically change it's mechanisms in order to achieve something, it just executes.

Humans (and arguably other animals and groups distinct from indiiduals) may have purpose, and may infer purpose on things that don't have it intrinsically.  Even then, there are usually multiple simultaneous purposes (and non-purpose mechanisms) that interact, sometimes amplifying, sometimes dampening one another.