Tom,
I do think that, as a general rule, new courses are more expensive to maintain than old courses due to design and engineering changes - more irrigation heads, primarily, but also some design features.
However, after reading information from John Vander Borght in the other thread on maintenance budgets, and watching what is happening in the various markets, it appears that budgets are going way up for existing courses. In the other thread, John pointed out that in Pittsburgh, the average maintenance budget has gone up by $150K-200K in a few years. The cost of most maintenance items (including labor) hasn't gone up that much, so it's got to be that the customer is demanding more in daily conditions, particularly at the high end. I'm not sure what would change that.