Linux is (and has been for quite some time) widespread as internet servers and, to a lesser extent, as business data servers. However, people have been saying for years now that it will become widespread on the desktop as well, and it hasn't happened yet. As others have said I think it has to do largely with requiring terminal access for what should be even simple things, and especially whenever anything goes wrong. Unfortunately, because of the open nature of Linux, there is no central control to spearhead a resolution to this problem, everybody goes off in their separate directions, and the result is not exactly user friendly. This has resulted in the myriad of distros, which is quite daunting to a new user (even Microsoft Vista variants aren't this bad). Unless and until Linux is taken over by a single organization that can drive its development I don't see this ever changing. So no, I don't see Linux as ever becoming more than a curiosity on the desktop.