This discussion was also happening with Wikipedia 20+ years ago. Whether you believe Wikipedia is an authoritative, trustworthy source in 2025 is irrelevant because back then, it was not yet seen as such.
Putting aside the person behind Grokipedia, the reason for its creation, the manner in which information is 'acquired', the explicit and overt political goals, the low quality product, the accessibility shortcomings, the poor UX, the corporate control... Grokipedia is about 7 minutes old and is not yet proven to be of any value to the concept of information sharing or to the world as a whole.
I agree Kagi should absolutely seek out options to add alternatives to Wikipedia (like Britannica) to allow users more choice.
Ultimately, Kagi's product is worth paying for because it prioritizes surfacing high quality, human-centric, user respecting sources.