Xenix had competition in offices: most people wanted wordperfect and Lotus 123 and some way to share their files. In an office with a netware or banyan vines server, xenix really didn't have a place.
The netware network stack was tiny compared with a full blown tcp stack to talk to xenix, which used to matter a lot before windows for workgroups. The graphics in a PC were pretty ordinary compared to a Sun or an SGI box, so as a workstation xenix couldn't compete there either.