CBM,
I've never seen Easthampton, so I'll accept your categorization that it's penal.
I'm forced to call Easthampton an exception because its form doesn't appear in appreciable numbers throughout the golfing universe. It is rare, not common.
In the golfing universe of 1920-1930, penal courses and penal features were more common than rare.
Pete Dye was known for his penal designs, but perhaps he benefited from timing, when developers asked him to design very HARD golf courses like TPC and PGA west.
It's not that the cadre of designers who worked for and were influenced by Pete can't design a penal golf course, it's just that developers aren't requesting it, the market's no longer there. New penal golf courses are "Mostly Dead".
I can't tell you the time line or the architect responsible for the demise of penal architecture in America. Those with the time and research resources could probably establish a time line, and the roots of a cultural or philosophical change away from penal design, manifested through a number of architects, or a generation of new ones.
I don't think one cataclysmic event or architect eliminated penal design, I think it may have just been evolutionary.
I've attempted to answer your questions, but, you've avoided answering mine, which are material to my position.
Name just 10 penal golf courses designed and built between 1950 and 1990, a forty (40) year period, in each of the following categories.
Resort
Residential Community
Country Club - Mixed
Would you agree that you could name an overwhelming number of non-penal courses in those same categories within the same time frame ?
Let me know if you feel that the vast majority of courses renovated (worked on) since 1950 have been hardened or softened for their members.
Let me also know if you feel that the percentage of Penal courses in existance today is equivalent to the percentage in existance in 1920-1930.
I think that one can prudently conclude that the design and use of penal architecture, penal features doesn't exist today, as it did at several points in the past.
But, that's just my opinion, and we just disagree.