Because people expect another person to be a amusement park- a show. They are not. They are a information processing system- often not even fully self-aware of the information their subconcious weaves into complex ideas. Surveilance and reflection does not improve that performance or allows to reproduce it. It instead produces distraction.

This is why you can not "interview" innovative or creative people- and only get a flat "imposter" image of the creative person. The observation hinders the process and all you get is basically the "house keeping" routines- weaving together some plausible stories, on how a "idea" came to be.

The true process is a walk in the mountains. Some scribbled notes. Glued together during some conversation on a similar topic with friends. I always found it fascinating, how the "iterrators" can dismiss something/someone that clearly works- just because they can not dissect and reproduce it.