John, good question. I can only give a short-hand answer here.:
Most of the classically trained designers did not survive in the business (if at all) through WWII. Trent was pretty much alone, Langford and Diddle being the only exceptions, and they were not major presences or industry leaders.
Jones set the tone, and it all had to do with turning your back on the past and starting anew, fresh, this time with earth-moving and bulldozers. Budgets were miniscule, they used the equivalent of D-3s and D-4s for everything, no hand work, no small machinery, and most of the stuff looked manufactured by road builders, which it basically was. There were a very few exceptions to this style, but it was dominated by Trent, who became soo busy he simply replicted his own work everywhere, and then essentially the same formula was used by Wilson, Maples, and Cobb. They didn't usually build bad courses, just big ones with bland features and little character or depth. The advent of USGA spec greens in 1960 took all of the early art away work from creating interesting, push-up greens.
The rebirth of style started with Dye in the mid-1960s; he rescued an art that was asleep for 25 years.