While NeXT might have been a commercial failure, the vast majority of entrepreneurs can only dream of having such a business once in their lifetime. In the end, NeXT was acquired by Apple and the foundation of their operating system became what is now OS X. NeXT would not be called a failure if any other person had founded it - it just seems less successful by comparison in the light of Jobs' other endeavors.
If NeXT hadn't produced a pre-emptively multitasking, memory protected, highly object oriented operating system and software development ecosystem, NeXT wouldn't have been acquired by Apple, and Apple wouldn't have had the key technology that has powered every major success they've had outside of the iPod in the last 10 years.
Remember that Apple wasn't shopping for Jobs, they were shopping for a modern OS; they only turned to NeXT after Gassée fucked-up their deal to buy Be.
