They realize it - remember Jobs' "truck vs. car" analogy - and they're betting that 90% of the population's needs are better met with a car rather than a truck.
With PC/Linux(/Windows) you can get either the practically grandma safe Ubuntu or Mint installation with everything working, or you can go for Gentoo or Arch or even just a customized Ubuntu or Mint when needing more freedom.
There's a thin line between recognizing user needs and deciding user needs.
In any case, I think we underestimate the market and normal people in these conversations. Any iPad user can freely access the internet and quickly find out that their device is basically unusable for programming or a lot of forms of content creation and even gaming. As software eats the world, the cachet for programming has never been higher, especially among the kids/teens we "worry" about, and the tools have never been cheaper or more accessible.