I think the author is mostly saying that, unless you site is horridly designed, that incremental updates where required can have just as much impact on the bott

I think the author is mostly saying that, unless you site is horridly designed, that incremental updates where required can have just as much impact on the bottom line as complete sitewide redesigns, especially when the point of new design is often misguided, i.e. simply trying to keep up with the latest design trends.