It depends on the building where the elevator is located. Security cameras are installed in places like malls and office buildings, and it doesn't mean you're being stalked there. These cameras provide you safety, so it's a necessity to have a security system in busy places like that. But actually, even I recently installed https://ajax.systems/ to my house to make sure I'm protected, so it's up to everyone.
Yes quite often there are cameras in elevators. How well they are watched depends on the place of business.