XOOPS is really nice php platform, everybody knows that
The big, really big chagrin are themes
What do you think, what makes wordpress (in example) most preferred system? The themes of course. They are nice, completed, modern, easy to use and etc.. people like it and choose it for his sites.
The contemporary webmaster is not this we know - with excellent html, php, css, java and etc knowledge. NOW EVERYONE MAKES A SITES, just because there is a web platforms like WP
OK I dont like it very much, its heavy and intractable for customization, but people like it not only because its easy, there is millions themes and plugins. And although most site owners dont have special skills, they wants to have unique sites, like well-knowledge webmasters, and guess - modern system like wp namely give them this opportunity
So if anyone wandering why fewer people use xoops, the answer is: its not modern because of its theme poverty
XOOPS needs from 100x guys like Angelo (just good example)
Sorry that I cant help, just note this fact, like a really good xoop fan
But I believe in XOOPS and still waiting 2.6 with the promised option "clean url", rewriting all system, modules and theme paths