Where you may have trained that may have been the case, but it isn't standard by any means. And considering some the anecdote, you must have been at either a very large or a very very subspecialty driven hospital. I'm not at a tiny hospital by any means and none of that is the case here.
And there is a HUGE difference between being hands on and actually being primary on a pt in the ICU, I have NEVER seen GI, do any procedures in an ICU, outside of a scope, hell, I placed the last blakemore tube while GI was out using up to date for instructions on using it.
renal, does renal still do they're own dialysis catheters anywhere?
ID, hell, I've never even seen they do a procedure. None the less, none of the other specialties mandate ICU rotations as part of they're training, except maybe CCU, but I'm sure many CCUs are like mine, pt comes in with 3rd degree heart block, we can't take that because they have too many medical issues, to MICU they go, and we get consulted for CC management on the rest of their CCU pts.
But back to your original point, about pure pulmonary fellows, there sent that many, last time I checked there was 6, and one closed and rolled over into our pulm-CC fellowship. Compared to 125 pulm-CC fellowships.