The text of the measure refers to "compensation", of which it gives a specific definition that includes commissions, bonuses, and equity (specifically mentioning stock options). The $1 salary CEO isn't excluded if they also have a huge equity package.
Although it doesn't mention capital gains, so if the CEO owns a significant part of their company already and doesn't have an additional vesting schedule, then they could make personal income from appreciation of the business that wouldn't be counted towards this bill.
Our billionaires are billionaires from their ownership stakes in the companies they founded. For instance, Jeff Besos only makes ~2 million per year in total compensation! He would pay no more in taxes if he were to move to SF (from this particular bill, anyway).
Although it doesn't mention capital gains, so if the CEO owns a significant part of their company already and doesn't have an additional vesting schedule, then they could make personal income from appreciation of the business that wouldn't be counted towards this bill.