All I can say is that in my experience I've only witnessed (and on occasions been, sadly) the dysfunctional kind of EM+IC. I've never witnessed it working well, which is what I'm basing my objections on.
The best managers I had were full-time managers (with an engineering background, which meant they understood the technical constraints); the worst managers I've had were either 100% non-technical, or EM+IC roles which just couldn't keep their paws away from coding.
All I can say is that in my experience I've only witnessed (and on occasions been, sadly) the dysfunctional kind of EM+IC. I've never witnessed it working well, which is what I'm basing my objections on.
The best managers I had were full-time managers (with an engineering background, which meant they understood the technical constraints); the worst managers I've had were either 100% non-technical, or EM+IC roles which just couldn't keep their paws away from coding.
My 2 cents, anyway.