the real culprit when it comes to shrinking greens?
I think that a huge drawback of maintaining a collar cut is the green mowers are always trying to cut as close to the collar edge as possible without scalping it, which results in the collar getting bigger and bigger. Then, because the collar mower is always mowing a predetermined number of loops around the green (usually 1 or 2) the rough begins to encroach into the collar.
I've noticed that since we eliminated these cuts our greens aren't shrinking anymore. I think its because the difference between the height of the green and the height if the rough is so obvious that its nearly impossible for the turf to go from .1" to 1.5" without noticing.