TBH William Osman's been pretty open about this event not being profitable yet, though having the support on the YouTube/Sauceplus side, he hopes that will fill in the funding gap.
Trade shows/conferences without a massive corporate sponsorship backing (e.g. like many trade shows today) are definitely risky, financially.
More on Wikipedia: https://en.m.wikipedia.org/wiki/Maker_Faire
They're actually back now, but in a less expensive venue in Vallejo: https://bayarea.makerfaire.com/
Next Vallejo event is 26-28 September 2025.