MS Windows popularity

This is likely true. Nintendo is probably also "here to stay." However, I like computing; therefore, I choose a computer with a powerful operating system, not a lowest-common-denominator piece designed for "everybody."

Linux is quite positively here-to-stay because of its open-source nature (Linux cannot possibly be put out-of-business). It is a standard selected for countless projects that are not going to go away, and some of them are quite "mission-critical." Try the International Space Station, for which Linux is the operating system (http://www2.linuxjournal.com/lj-issues/issue59/3024.html).

Plus, never underestimate the strength of the Linux community. Linux is "here to stay" at least for the computer avant-garde. Many Linuxers do not even want Linux to become very popular because they fear it could "dumb down" the elite Linux platform.