A recent article in Fast Company asks a great question: Why Can't the World's Best Architects Build Better Web Sites? It goes on to analyze a number of these to show where/how they fall short.

A simpler explanation that is not discussed in the article is that architects are 3-d thinkers/designers...whereas websites are (currently) a 2-d experience. What you'll find in a lot of architects websites is an attempt to transfer the 3-d experience into their websites. This, ultimately, leads to decisions that affect usability and SEO. Even print designers find that moving from their medium to interactive design is a daunting challenge at best.