In fairness their children haven't done anything in the tech space or much of anything near tech/science. Of the 7 children: Jobs kid's one is a writer, celebrity son, goes to school. All Standford grads or attending. Of Bill gate's kids one goes to art school, the rest not much.
I would not copy them unless you have the billions for them to fall back on.
In higher level education they also use the familiar chalkboard rather than electronics. I use this not to say the merits of their children's occupations (regression to the mean is common in families of great achievements) but as a warning of what people in tech see as a threat to their own children's well being. Electronics are wonderful but not for everything. If screens work better for you, perfect! They have been a hindrance to me, addiction to screens is very common today and I am weak enough to fall into they category.
Creating something motivates most of the people on this planet, and without going into specifics, I would claim that Gateses and Jobses of this world are not all that rare as far as their abilities are concerned. Situation and, well, luck, are a big part of where life takes people. And having been provided for will discourage most from being as driven to "succeed" (in either financial or tech/scientific sense, two most common accepted ways to success on HN).
Which is to say: don't judge according to your standards of "success".
And raising kids is anything but science, unless you have such a large number of them that statistics applies (though even then, you'd probably be breaking a bunch of laws if you tried to be scientific :)).
As such, addiction to screens is usually, imo, an addiction to specific type of content, or rather interaction (or lack thereof) type.
If they're not that rare, why are they rare?
Where did I make a judgement on their success or even use that word? Are you replying to the right person?
I doubt you've looked into the theory behind screen addiction (I didn't believe it either). It's the vivid colors and the effects they have on your brain according to neuroscience, plus the manipulation that companies utilize. I've changed my screens to grayscale and have no such problems now.
I think I explained why they are "rare" even if they aren't: circumstances, motivation and drive to succeed in a particular way, a way you classify as "great achievements" (not success, sorry for equating it: I might have missed some nuanced differences there).
It's actually quite interesting that you even consider Gates and Jobs having "great achievements" (other than business success, which is clear), yet condone screen addiction (which their core business were mostly about).
A quick search does not give me any study relating technical properties of screens to addiction-like effects: do you have any pointers? (Other than the common "LED-light-interferes with sleep patterns".)
I would not copy them unless you have the billions for them to fall back on.