Having been around when Quark started to fall behind and then switching to InDesign myself, I don't agree with you. QuarkXPress was crap, and Quark had no interest in modernizing their software. It took forever just to get native OS X support, and the software lacked a lot of InDesign's print publishing features. Desktop publishing has always been a Mac-centric affair, and ignoring Mac users was a pretty poor decision.

Quark tried to milk its customers dry. It did and then they moved on. They never diversified their company, and the one product they made was becoming despised.

Final Draft is a good modern-day version of QuarkXPress.