An NLM, Do doo be-do-do
(or 'No Laughing Matter' as a friend used to call them).
The thing that did for Netware was the irksome Novell support priesthood who had every incentive to insist that computer networking was a complex business. Then when WIndows for Workgroups (or Widows for Wombats as we called it for some reason) came along, a small office could string wires between a bunch of PCs and have a peer to peer network.
Our Netware preiesthood were wildly pleased with themselves and wildly unhelpful (*) - now, clearly, for a big organisation Netware was probably better at the time, but the strung together WfW machines acted as a bridgehead for Microsoft.
(*) and I don't say this just because one of them was a short bearded berk (not to be shortist, or beardist or, indeed berkist) who, despite being a colleague, called environmental health to complain when our burglar alarm went off and didn't cut out.