From https://kagi.com/pricing:
Why does Kagi cost $10/month?
Our proposed price is dictated by the fact that search has a non zero cost. With other search engines, advertisers cover this cost. But it costs us about $1 to process 80 searches.
Someone searching 8 times a day would perform about 240 searches a month, costing us $3. An average Kagi beta user is actually searching about 30 times a day. At $10/month, the price does not even cover our cost for average use, and we are basically betting that average use will go down a bit with time because during beta people may be searching more than normal due to testing etc.
Our goal is to find the minimum price at which we can sustain the business. If it turns out that we have more room we will decrease it. But it can also be that we may need to increase it.
The free plan will be limited to 50 searches a month (and this too has to be paid by paying customers which makes the above math even harder).
The current pricing is optimized to offer a user the least expensive plan possible. The current $10/month offering pays for the estimated average amount of searches for one user, with some small amount added on top to subsidize free users.
My request here was to offer a family plan with a price that's appealing enough that people don't simply share accounts. I ask this after reading, for example, that Netflix thinks a significant cause of its slowed revenue growth is due to shared accounts. I also ask this after considering my own personal feelings based on the pricing of (what I feel are) comparable services that I pay for. But like you implied, the money has to come from somewhere. I feel that single-user plans should subsidize the family ones, personally.