Being charitable, I am assuming you are implying that someome would turn on their camera to show that?

Zoom webinars like this one are not the same as a your average zoom call. You can see the hosts, ask Q&A question, and talk in chat, but you don't see the other viewers of the call

It would be technically difficult to have calls this big and still support having every single person in the call being able to show cameras/unmute any time. Even if only 1% were unmuted, I doubt zoom's servers could support mixing the audio from thousands of sources in real time and then sending it to hundreds of thousands