I think it's safe to say that slower green speeds are a condition of the past.
I've generally opposed flattening greens to accomodate higher green speeds.
I think compromising contour and/or slope in the name of faster stimps is an architectural mistake.
The putting surfaces at MPCC aren't severe, either in contour or slope, although, there are a few with dual tiers with significant elevation changes, but, those tiers are more about one's approach than one's putting.
MPCC's greens enjoy a unique micro-climate, one where moisture in the air, is beneficial.
Some call if fog.
It comes and goes.
In addition, MPCC and the courses in that area aren't affected by weather anomalies.
They don't tend to get 90 degree days and as such, I think they can "dial in" the conditions the membership desires.
Putting on them was a culture shock to me, but, I adjusted and after playing them for a few days, putted rather well, although, those cups have to have the sharpest edges I've ever seen.
Even in a similar micro-climate, configuration of the greens can make an enormous difference.
Anyone who's played Baltusrol Upper and Lower can attest to that.
If both courses stimped at the same speed, the Upper would be far more difficult to putt, due to contour and slope.
So, speed is not a universal or general condition, but, one confined to the club and it's particular greens, climate, etc., etc..
MPCC was simply spectacular and FUN to play.