The other set has nice clean segmentation of job roles, you are one of:
The first set tends to spend their time doing, the second set spends their time communicating. It is not a “big firm” versus “small firm” thing; although bigger, older firms will often shift into the second set as their mature and a different class of people start being hired. The first set has accountability being very clear. The second set has fingers pointing back and forth resulting in a Gordian knot of responsibilities.
Personally, I prefer the first pattern because things get done….