While at the top of the heap, Novel were extremely arrogant. They couldn't make a go of Wordperfect - they took the DOS product and tried to put a Windows wrapper around it, thereby producing a slow unstable product; this was exacerbated when they brought out the java version which was a bigger disaster. They didn't win any brownie points when they offered, via the internet, to give the product to anyone who wanted it.
The second major mistake made by Novel was to try and force NDS on the small user. It made Netware a more difficult product for the small shop, without experts, to deal with.
The final mistake Novel made was to keep on saying "Netware is not an OS, it's a NOS". Windows and Unix/Linus were OS's and therefore one could run applications on them. Novel's attempt at OS support, NLM's, were totally unstable, when an NLM crashed, so did the server. Also writing NLM's required very specialist development skills and thus there were very software houses writing apps, unlike the Windows and Unix/Linux markets.