Hmm, seems to be in the top 5 results for most related searches in DuckDuckGo. I guess you're talking about Google, which is ranking results differently, somehow. IIRC, (amongst other things) Google ranks sites based on how many high-ranked sites link to them - DKWiki's link from Bulbapedia and the like should help, but Wikia wikis are linked from Wikia central and loads of other Wikia wikis (I think they put random links in sidebars and things? Tried to check, but it's hard to tell since images no longer work at Wikia for me, and the whole network is fundamentally broken...).
When searching only "donkey kong wiki", there was no problems. But if I wanted to search something like "cranky kong wiki" or "cranky kong", DKWiki fallen to the bottom of the page.
(But really, may I ask what's the point of DKWiki when Mariowiki also has the same articles, but better? Not trying to start a flame war here.)