I don't think coffee's a great analogy - it has far more utility for me, I don't buy it as a service, and it costs me roughly £24 (what, $30ish) a month in beans.
I'm not seriously suggesting it because I think comparing prices of different things to determine value very quickly gets silly, but a closer comparison might be Netflix: Kagi would cost me about as much per month for search as Netflix. Silly, as I said, but if I tried really strictly to pay for things according to relative value or utility to me, there's no way that would make sense.
Part of the problem is asking me to switch from free I suppose - if DDG suddenly started charging me $5 I'd be more likely to pay Kagi $10 than I am today if that makes sense.
Laundry detergent and breakfast cereal both come in a box in the supermarket, but it doesn't make the products comparable. A house and a car both have a door and you usually sit inside, but it doesn't make the products comparable.
Netflix is a great bargain (for those who enjoy their offerings), and I think people are shooting themselves in the foot by dismissing other great services because they've somehow tricked themselves to thinking they should be compared to Netflix only because they're offered through a digital screen.
Though I'd stand by Netflix as a better comparison to Kagi than coffee (as in the comment I was replying to) to anyone who insists on doing it.