Cool discovery. As for why so many eggs there, I don't know, but if I had to hazard a guess, it was probably a big nesting site way back when. And whatever happened at the site to kill the dinosaurs that used to live there and their nests, the right geologic forces came together to fossilize the eggs at the site and preserve them long enough for humans to discover them. Most things do not get fossilized,
it takes the right geologic forces coming together in the right way at the right place to happen, especially on a large scale.