I wouldn't even know what metric to use to quantify that. Number of tables? On the order of hundreds, probably low hundreds... definitely not thousands.
It may just be that I've been lucky in that the data models I've worked with have been things that map well to using Hibernate. I will say that I haven't worked with a lot of data models where you need more than 3 or 4 joins in any given query. I know some people write far more complex queries than that, and maybe those are the kinds of scenarios that Hibernate doesn't handle well?
The problem with Hibernate is I have to learn all of these Hibernate quirks to maybe get decent speed out of a system, when I could have just written SQL and been done
Do you hand-roll your own caching mechanism when just writing plain SQL?