Re: Linux is not dominant on servers:
Are you not aware Linux runs happily on IBM Mainframes, it's even heavily promoted by IBM for those who work with Linux but want the perceived advantage of a mainframe compared to other options (e.g. Intel server clusters)
Disclosure I now a few people who were involved in getting NIXes to work on IBM kit way back in the day that led to current state of NIXes running fine on System Z etc.