Yes, in a 50k employee company, the CEO won't know every single employee and be able to vouch for their skills and intentions.
But in a non-dysfunctional company, you have a hierarchy of trust, where each management level knows and trusts the people above and below them. You also have siloed data, where people have access to the specific things they need to do their jobs. And you have disaster mitigation mechanisms for when things go wrong.
Having worked in companies of different sizes and with different trust cultures, I do think that problems start to arise when you add things like individual monitoring and control. You're basically telling people that you don't trust them, which makes them see their employer in an adversarial role, which actually makes them start to behave less trustworthy, which further diminishes trust across the company, harms collaboration, and eventually harms productivity and security.