For the first time, individual hackers could afford to have home machines comparable in power and storage capacity to the minicomputers of ten years earlier - Unix engines capable of supporting a full development environment and talking to the Internet.
A critical factor in its success was that the X developers were willing to give the sources away for free in accordance with the hacker ethic, and able to distribute them over the Internet.
In early 1993, a hostile observer might have had grounds for thinking that the Unix story was almost played out, and with it the fortunes of the hacker tribe.
Thompson and Ritchie were among the first to realize that hardware and compiler technology had become good enough that an entire operating system could be written in C, and by 1978 the whole environment had been successfully ported to several machines of different types.
If Unix could present the same face, the same capabilities, on machines of many different types, it could serve as a common software environment for all of them.
Linux evolved in a completely different way. From nearly the beginning, it was rather casually hacked on by huge numbers of volunteers coordinating only through the Internet.