I'd put a slightly different spin on it- sure, junior positions will be automated and commoditfied, but I don't see senior salaries going down. There's a key difference between software engineers and doctors:

No matter how good a doctor is, they can only treat so many patients and/or train so many juniors. A software engineer can scale almost infinitely in some respects. In this they are more like the investment bankers you mention, indeed in some circumstances interchangeable