For the burger metaphor, you need to have leverage over the employee to make them not speak. No one at Burger King is getting severance when they are kicked out, let alone equity.
As for other companies that can pay: I can only assume that the cost to bribe skilled workers isn't worth the perceived risk and cost of lawsuits from the downfall (which they may or may not be able to settle). Generative AI is still very young and under a lot of scrutiny on all fronts, so the risk of a whistle blower at this stage may shape the entire future of the industry at large.
As for other companies that can pay: I can only assume that the cost to bribe skilled workers isn't worth the perceived risk and cost of lawsuits from the downfall (which they may or may not be able to settle). Generative AI is still very young and under a lot of scrutiny on all fronts, so the risk of a whistle blower at this stage may shape the entire future of the industry at large.