It depends on how you’re defining as the job.

The nominal surgeon usually does the “heart” of the procedure: replacing your ACL, removing a tumor, etc. Their assistants just get you into/out of the state where that happens.

Surely you don’t expect the surgeon to personally do everything related to the case, right? Wash the drapes, prep the instruments?

They most likely didn't though as it would be a flat out lie. He probably explained the procedure etc but never commited to doing it himself specifically.

Or maybe something more important came up just prior. Ultimately people have the learn and have a go at some point - with your attitude they would be no more doctors.

There doesn't have to be any deception on anyone's part for their to be new surgeons. If a new surgeon is doing the operation, he/she should be the one to meet the patient and explain the operation

Exactly, there are "teaching" hospitals where the entire premise is that it's for newer doctors to learn. They're usually cheaper as well and people know this.