Partly because this hasn't cast doubt on their competence. Like, they may be evil as shit, but that doesn't mean their medicine is bad, or doesn't work, or unreliable, or anything like that. It does what it is supposed to do, reliably. But also it has been pushed hard on people to make them addicted. Literally the first people who will be vaccinated are the people prescribing the medicine. If you give them a shit vaccine, they'll be pissed at you, and it won't be just that you did something evil, you stained your reputation irreparably and now everyone knows you as that company that makes unreliable stuff. If there is an alternative to your medicine everyone will want the alternative, and doctors will be mad at you too so that's what they're gonna prescribe.