"Boiling wort for a long time caramelizes it"
It actually might though. We've got 230F as the caramelization temp for fructose. I am not 100% certain that the temperature on the inside surface of the kettle, on the bottom right above the flame, does not exceed 230F if the burner is hot enough or the pot is thin enough. Supposedly a jet burner can melt a hole in a stainless pot full of water.
Also, the presence of amino acids and other wort components and the pH of the wort will lower the caramelization temperature. Here is an article that showed caramelization of maltose at 130C peaked at 60 minutes, but maltose supposedly only caramelizes at 180C. Their marker of caramelization is "5-hydroxymethyl-2-furfural (HMF), the main characteristic caramel product". They call it HMF, but I'll call it 5HM2F (see below). http://www.ncbi.nlm.nih.gov/pubmed/12395187
Then there is this article where they analyze the volatiles from unhopped wort during the boil and find 5HM2F. http://pubs.acs.org/doi/abs/10.1021/jf072619r
On the other hand, some sources say HMF is also formed by Maillard reactions, however some other sources refer to 5HM2F as 5HMF, so it is not clear if we are talking about the same compounds across the board.
Bottom line, I have questions about the research and I'm not 100% sure they are right about caramelization happening. On the other hand, I am not 100% convinced that it can not