Short answer: the Internet took over. By that I mean other databases proliferated and made it easy for users to find countless different family files which we can simply download. There are generic Revit family websites such as Revit City and Arcat.com , and there are Revit files created by their manufacturers for windows, doors, and plenty of other items. Hubs exist for such product-specific files such as BIM Object where you can download many companies' Revit family files of their products.
There are also many families included with out-of-the-box Revit installations now, many more than there were a decade or so ago.
And, if you can't find what you want to model in the out-of-the-box Revit library nor on the Internet, then you can create a family yourself in the Family Editor. See this link if you don't have the default Revit library loaded: https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/sfdcarticles/sfdcarticles/W...
I have created myriad door and window families myself when I couldn't find what I wanted in these two locations (or I didn't want to spend time on possibly-futile searches). So modelling the doors you want may be the way to go, or check out online databases.
