Quark was the Adobe of their time. If you thought the licensing of Adobe is intrusive now you should here the stories of Quark licensing in the 90s. They took piracy paranoia to an insane level. And the companies that bought Xpress sometimes reverted to the pirated copies because at least those worked.
Quark became more and more user-hostile through the 90s, basking in the dominant market share of their (essentially) single product. Prices went up, the feature set stagnated, anti-piracy measures punished the honest, and Quark tried to push ill-conceived "multimedia" and web features into the product. Focus was lacking not only in their product, but in how the company was run: development and support were moved to India, and then a few years later moved right back. And despite all this, in terms of dominance Quark XPress was like the Photoshop of its time: with all the professional workflow based on the product, the ecosystem of expensive plug-ins, and the people whose jobs were practically defined by their Quark expertise, it was difficult to imagine how any competitor could gain traction.
But Quark's unpopularity with its captive customers created a fertile field of potential good will for anyone with the gumption to try jumping in. And the nimble upstart who finally gained traction was of course Adobe. InDesign was cheap, good, addressed many of the long-term unresolved Quark pain points, and, despite bugs and shortcomings, held the promise of a future outside Quark's cloak.
A decade later, where are we?
The creatures outside looked from pig to man, and from man to pig, and from pig to man again; but already it was impossible to say which was which.
Indesign 1.0 definitely did not. It was Quark's market to lose and by Indesign 2.0 prepress shops were just starting to take Indesign files. The rest is history.
The designers I worked with at the time were early proponents of InDesign and basically told printers: "If you want our business, you'll have to buy InDesign." They did.