I know I can perceive a difference. Even if it's subtle, it takes, what would be a good beer, to a great beer.
With all due respect, how do you know you perceive a difference? I'm not saying there isn't one, I'm just truly curious if you've done blind comparisons? I'm a huge believer in the subjectivity of preference, so what's good to one might be great to another, hence my adherence to the "to each their own" mentality.
Tradition is often an incredibly strong influence, particularly in more collectivist cultures. That and the fear of losing product/money should something go wrong are at least reasonable possibilities as to why some (not all) German brewers continue utilizing conventional methods.