Ornamentation and architecture

Ornamentation is a crime - Adolf Loos

One of the most famous architecture quotes in history, and one of the founding principles of the modernist movement. Adolf Loos claims that ornamentation causes objects to go out of style, and thus become obsolete.
Until the 20th century, most architecture styles had ornamentation, Classicism, Baroque, Gothic, Art Nouveau, to name but a few. Are they out of style?
Well, they definetely are styles. Modernism was never concieved of as a style. It was supposed to be a revolution, that would eliminate the need for styles, and its buildings would never go out of fashion. I suppose it's Ironic that nowadays Modernism is considered a style, and not only that, it's probably the style, that is least in fashion at the moment.
Why is this? Is it because it hasn't had a chance to come back to fashion yet?
I think, that it is in fact, due to its lack of ornamentation. Sure, a building can look good without it. There are countless beautiful non ornamented buildings, but there also an awful lot of crap. People like ornamentation. Need proof? Go to any city, and look at what buildings have the most tourists taking pictures of them. They are the cathedrals, the palaces, the gothic, the classical. There are very few people taking pictures of modernist tower blocks.
If this is the case, why are there so few buildings being built today with any ornamentation? Is the modernist state of mind still overwhelmingly the case?, or are architects just afraid of breaking precedent?
Maybe the problem is that no one knows how to create a building with ornamentation in this day and age. How do you add ornamentation, without creating pastiche? How do you ornament a building to reflect the society of today? How do you avoid being tacky?
I don't know, but maybe it's something we should be thinking about, as architects of the future.