S-100 was very, wild era and multiple types of processors and standards, multiple stuff to contend with to match and mix to make a working S-100 system takes lot of expense, technical and software knowledge. Once PC clones came after PC XT, and especially Compaq, S-100 stuff died out suddenly and was very dead just before 1988 or so, due to early high quality clones like Zeos, PC limited, AST, Compaq, so on) started to come out with 286 and 386 machines. Because these were successful at selling computers that is ready to go by plugging together and start the DOS up or windows with no need for dotor's thesis.

All these odd ball computers like Osborne, MBC-555, etc are another perfect examples of proprietary hardware and software from that same era.

Cheers,