What if CBM's father had not sent him to college in St. Andrews?
This is my favorite answer so far... Golf courses would still have been built at the same rate in the US, but the working architects of the time would have been FAR less motivated to build truly outstanding courses. They could have been careless and thrown in far more dull holes and no one would have noticed.
Raynor would not have been hired as a land surveyor, and there would have been no one to build in Macdonald's strict style. A style that evolved into sharp angled bunkers, geometric shapes and a clearly engineered look. A style noted by today's minimalists, and THEIR look reflects their reaction.