How is it even possible to learn this much math or organize such complex ideas. Undergrad comes nowhere even close to this. I guess the leap occurs in grad school. But even though, this is way more advanced than 99.75% of math papers I have read.
In my limited few years of doing undergraduate / graduate research in this kind of field, and thus having to read research papers like this, I can say that this is BY FAR the longest paper I have ever encountered. Several times over. Forget writing a 177-page paper, how do you even begin to read this? Yes there is a helpful outline on page 6, but sheesh!