story
Back of the envelope:
The Bing API costs about $0.015 per query at the most cost effective tier. Kagi's highest revenue per query pricing is $5/300 queries = $0.166 / query. That's pretty slim margins, and only made worse by the $10 tier.
Now, they can of course start doing exclusively their own crawling, indexing and ranking and avoid paying some larger search engine for API access. But for that to be cheaper, they need orders of magnitude more scale