Surely Clarity.fm can analyze its internal search queries and categorize the phrases according to intent.
For a given query category, Clarity.fm staff can measure the ratio between search volume and the number of profiles appearing in Clarity.fm's internal SERPs. If the ratio is high, then there's an unmet demand for experts.
It does no good to ask what sort of experts are absent without referencing visitor demand. For example, there are no experts on Clarity.fm for training tigers to perform in Las Vegas magic acts. But if Siegfried or Roy showed up, they'd be 1 expert too many.
It's also worthwhile to compare the number of qualified profiles (for a category) to the number of profiles that appear in search results here at Clarity.fm. Ideally they'd be one and the same. But in practice, less than 100% of profiles will show up in query results even if the experts do possess relevant skills.
That gap can be closed by Clarity.fm staff with search algorithm improvements or by the experts themselves, whose profiles may need to be rewritten to be search-engine friendly. ... Yes, Clarity.fm is a search engine; so some SEO might be prudent.