I like to imagine they couldn't make a dent in the Mac market because their products were too ugly to appeal to Mac users.
Sometimes I think I'm only half joking on that.
Back then, making software run on more than one platform was much more painful than it is now. Not only were the range of features provided by the OS vastly different, it was common to write performance critical parts in assembly - which made them need to be almost completely rewritten (there were macro assemblers that made that slightly easier). Unix was heralded as "open" (not to be confused with open source) because it was less painful to port stuff and make it interoperate with other Unixes.
Sometimes I think I'm only half joking on that.
Back then, making software run on more than one platform was much more painful than it is now. Not only were the range of features provided by the OS vastly different, it was common to write performance critical parts in assembly - which made them need to be almost completely rewritten (there were macro assemblers that made that slightly easier). Unix was heralded as "open" (not to be confused with open source) because it was less painful to port stuff and make it interoperate with other Unixes.