There's a limit to how long a search can be. If it was made much longer, then searches would slow down, the network would slow down incredibly, etc. & you'd get back less results because the search would run out of energy before it got any where as far as it can now. ie: limiting the search reduces traffic & increases search results. It's easier matching shorter searches than long-named searches.

If you're having problems finding something, try varying your search criteria. Use different search methods. eg: Just the artist or just the title or just a portion of the title. Personally, I generally use the Any Type search instead of the video or audio search type. It seems to bring in the odd more results. Varied perhaps which is sometimes good.