Rough areas are less philosophically problematic than green collars.
Why a green collar, maintained at a height in between the fairway and the putting surface? I don't know, unless someone at some time thought it looked good and others emulated the look. Seems to me it's just another maintenance problem, and it could be done away with, saving time, money, and heartache during that time of year when they burn out and look horrible (at least in the Mid-west).
As for roughs, it seems the idea is miss it a little and get a little penalty, miss it big and get a big penalty.
It seems that most intermediate rough cuts are four to six feet wide. The problem may be that they are not wide enough.
Imaging a narrow (15-20) yard fairway (1/2 in. or less) along the "line of charm," them an intermediate rough (1 1/2 in. to 2 1/2 in.)of some 15-20 yards on either side, and outside that- death by rough.
Coming to rest in the fairway is the absolute best situation, even better if one is in on the correct side of this ribbon of fine grass. The best angles, the opportunity to generate spin, etc. Coming to rest in the intermediate rough is OK, but no picnic- bad angles, "cuppy" lies, potential fliers, and perhaps a layup is the best option. One might even play to these areas intentionally if one supposed there was some potential gain.
But hit it outside this 50-60 yard corridor, and it's pitch out time.
This is not unlike many desert course, where the desert is the primary rough. Imagine Talking Stick North with 20 yard "fairways" and 2" "rough" everywhere else that's not desert, wash, or out of bounds. (I do not advocate changing Talking Stick. I love that course.)
One big advantage is only two areas to be mown daily- the fairway and the greens. The intermediate rough might get cut every third day, and the primary rough, if needed, once a week or less. Plus there are no small non-green areas to mow, saving time and money.
Having the entire course cut to one height is attractive also, if there are obstacles (rough covered hillocks, swales, streams, etc.) to add challenge, interest, and pleasure. In most US climates, something in the area of 3/4 to 1 inch heioghts seem appropriate for maintaning heathy grass.
I think I want to go see Diamond Springs.