I'll take a wild arse guess, Bob
MONEY!
For pros like Morris, Simpson (Archie), Braid, Park Jr., Vardon, Taylor, etc. the few pounds they could get for laying out a course was also supplemented by exhibition fees, clallenge matches against the local heroes and other emoluments. In the days when a top pro had an annual salary of less than 100 pounds, these perks were not inconsequential. In effect, they had to create the venues to provide them with their future income!
Snead, Nelson, Hogan, etc., on the other hand had not only a pretty decent playing income, as well as endorsements, they had the venues for their grey market income already built for them. My guess is that if Snead didn't have Greenbrier as his own private ATM machine, he would have designed and built it.
He, and the others, didn't need to......
Rich
PS--more heretically, I think that to them a golf course was a golf course was a golf course. This was probably the same for Palmer and Nicklaus etc., but by the time they started building them, it was a big business and big MONEY.
RFG