Seems that modern courses of the minimalist type seem to take up more land then those of the golden age.
There is some truth to that, but there are reasons other than what has been suggested.
For one thing, the classic courses were generally developed by the members of the club itself, and they didn't think about buying surrounding land for other purposes; whereas most modern projects buy big acreages to leave room for multiple courses, housing, or resort development.
Another reason is that we are selective in what we see. Peter mentioned Walton Heath, but in fact, it was designed over a huge open common; there are hundreds of acres of undeveloped heath around it. But we ignore those because we only see where the golf course is today. Sean is right, though, that not enough modern designs pay attention to minimizing green to tee walks, so today's courses are more spread out than those of an earlier age.
Whereas, High Pointe was a 320-acre parcel, and I routed it to allow for some housing development in certain areas, so the golf course really only took up 180 acres; but because those homes were never built it was perceived to be on a giant property. Likewise, Bill Coore and I did our best to get the routing for Streamsong as compact as it could be without tripping over each other's courses, but you don't notice that with so much undeveloped ground on the outside of the two courses.