I agree with you to some extent. But if the OP finds that the performance of certain parts are not up to his expectations after some period of time, then upgrade for better performance. There's nothing wrong with that.

If he waits for certain components to "wear out", then he may not be able to recoup the cost by selling the parts on ebay or craigslist. Bottom line is: ride the bike for lots and lots of miles, then make upgrade decisions based upon how you feel certain parts are performing. The OP's frame seems like a great frame as is the Allez's frame. In my case, going from Sora/Tiagra to 105/105 (9 speed) cost me less than $100 . After 2000 miles on Sora/Tiagra, I think it was well worth it based on how frequently I am riding and how often I use the front derailleur. Better performance came at a cheap price.