Probably the more relevant thread would be the recent ones on gca personality types, if it means predicting those who go into the business and are somewhat successful. There is a design personality, and it appears that over the decades, many gca's simply took a while to find out where they fit in! Maybe family pressures to go into some particular field rather than "waste one's life" in the golf biz?
I was lucky to know what I wanted to do early, for reasons posted here a few times. Others know it deep down, I suppose, or come to golf later in life and realize what they want to do.
I am also over run with applications, probably not as many as Tom D gets, but lots. Over the years, I have hired many young LA's (not much else, since I do prefer guys who can draw plans over those who might want to run equipment). It works the other way, too - where people with no real talent for design seem to be able to muddle through 4 years of design school, put together a decent looking portfolio - all it takes is your best graphic project to impress - and get hired.
I always gave them a six month probation period, but frankly, I could tell within weeks whether or not these guys had a chance at being good golf course architects (or designers of any kind)
BTW, I have yet to see a college student golf design project that was anything but laughable. A few had it closer than others, but some impressed right off with graphics, but if I looked closely at the designs, they were weak. Of course, I was in the same boat in 1977. I graded out a golf green, using some standard detail sheet I had seen. Hearing that greens needed good drainage, my plan was sort of domed in the middle, perhaps best for drainage, but also the absolute worst for holding golf shots. I took it in to Killian and Nugent, and they kindly told me that they made their greens more concave to help hold shots and the contour lines should have been inverse.
At least they hired me anyway, and I gave them seven years of good service. They could look past that school project, luckily and understood I had basic talent, and that they could teach me as I went. Tony makes an intersting point about the genetics of being a gca - I have been told that my family tree includes both English landscape painters and German engineers. I suspect the perfect gca is about 60% of the former and 40% of the latter.
Related, but my first week on the job they gave me a par 3 from a local reno to draw. It needed a pond, and I put one in along the front of the green. Nugent walked in, said he didn't like it and walked out. Thought he was mad, and that my career might span about three days, but about an hour later, he came back and told me his reasons - they did a forced carry a decade previous and were critiqued badly for it. Besides, in theory, they preferred angled and lateral water so as to always give the poor player a way around.
As someone stated, after the basics, you really start to learn gca when you work for a firm. Of course, the firm you start with sort of sets your career, as apprentices to Dye and Nicklaus have tended to go on to bigger things than apprentices for other firms. Mostly, if you get taught one way (in my case, less bold, more practical) it stays with you, and then you tend to get the same kind of projects your mentors got.