Sure, big frameworks existed back then, but they were all either

1. literally "frameworks" in the inversion-of-control sense — where your code is a script that runs "inside" the framework — and you don't ship the framework to your customers as part of your product, but rather walk them through getting it from its own vendor as a prerequisite step to installing your product (e.g. TeX); or

2. proprietary, not copyleft-licensed (e.g. game-console SDKs.)

If anyone has a good counter-example, I'm all ears :)

Especially since the term cathedral was popularized by esr to call out the development style of the GNU project.