As a very aware consumer I think it's fair, but a larger audience would be hard to convince :

• Internet is basically perceived as free for most people, in particular search engine is considered as one of the most obvious features as it is the entry point
• Google is still perceived as "the quality search engine" and others as the shitty ones that would trick you into using them during the 2000's via intrusive browser extensions. Recent popular alternatives always an argument other than the quality : privacy, charity, sovereignty, ...
• Most people can't make the difference between "Search Engine" and "Web Browser". I would say it is because of Google because Google Chrome successfully marked itself as "Google". This last one is scary to me, even people very confortable with computers can't make the difference and are not aware that a search engine is just a website and that it is not tied to a browser.

To convince someone to use Kagi, you must change their mind about these three points, and then convince them to spend 60$/year for it.