You better view papers as tools, facilitating further research and a citation as use of a tool. So a lot of citations indicate that a paper is a pretty useful tool for other people's work.
Usually with so many citations doesn't mean that there are 1700 independent citations in papers, only 1700 different papers. His paper is like a root of the deep citation tree. Many people cite their last papers, some recent papers in the area and the foundational papers in the area. So once you get a big foundational paper, you pile up citations for years.
It would be a nice project to get the ADG of citations with this paper as root and make a graph of it. My guess it that it will be something that looks similar to tree (each paper in a branch would cite a few recent papers in the same branch), but most of the papers in the tree would cite also the root paper too.
