That isn't humanly possible, you will blow out your neurotransmitters and not be able to think. Only being semi serious, but we can't make that many decisions a day.
Right, but you can imagine eg a hierarchy, in which case you might only talk with -say- 10 reports directly.
That isn't typically how abstraction is tallied. The ceo doesn't say they use 15k employees, or the programmer uses 30B transistors. Or the director uses 120 workers. You enumerate what you actually interact with.