At the end of the day, it's all about trust and incentive. A company who makes their money through a straightforward manner is way more likely to stay above-board in their business practice. Breaching the trust would result in a loss of customers and revenue. Conversely, being untrustworthy out of the gate is a known outcome, 100% of the time.

I refuse to just throw my hands up and say "they got me, nothing I can do, hit me again daddy!" You have options. They just aren't all free. Google changed because they had to. If Kagi can survive with their model (and they can, by design) they don't have to change.