To answer your question, I think Linux absolutely should target the mainstream, as it already diesinn some ways.

For example, by making Linux more accessible to the average user, the community grows, which will probably lead to more support, more software development, and so on.

It is true that not all users have the same level of computer skills. Especially for that reason Linux should become even easier and even more intuitive to use.

In short: the more use it, the more support it will get.