But my memory is that pervasive use of Factories came along many years later, and seemed to be driven by the perceived needs of TDD, for example to provide instances of mock classes in unit tests. And I thought the factory pattern itself came from the GoF, but I might be misremembering.
That said, I’m not trying to contradict you. It’s likely that there was more than one driver for the pervasive adoption of factories. In any case it was a bit of a nightmare for a while, hopefully things are improving there now.
It did, and GoF certainly influenced OOP outside of Java, too. But EJB created a need into which the Factory pattern was really the only solution. (GoF precedes EJB and even Java.)
But certainly its not the only thing; Java hit popularity right around the time GoF was most influential; OOP languages whose ecosystems developed earlier (e.g., C++) or later (e.g., C#, though GoF-heavy code isn’t unheard of there) wouldn’t be as influenced by it, all things being equal. Java just had the perfect combination of language features, early specs like JEE (which included Beans), and timing to be naturally inclined for maximum naive GoFism.
The Factory pattern’s pervasive use in Java was in large part a fairly direct consequence of JavaBeans requiring nullary constructors, so that the normal constructor work for a Bean had to be done elsewhere, i.e., by a Factory. Now, Beans was just a core part of the first-party enterprise framework that was central to the ecosystem and not strictly part of the language, but its not completely unrelated, either.