Yes, we do have around that number of tables which reflected into those thousands of models. Many of them are related to storing 'frozen' regulation data. One example: every X time we need to create something very similar to a IRS forms (electronic) and send it to a bunch of government agencies because the data sent must be available for reports we can't just store a text file. One of those regulations requires hundreds of tables:

https://www.fazenda.sp.gov.br/sped/downloads/GUIA_PRATICO_DA...

Some systems are very sensitive to transient data and pretty much needs to store all of it, depending on how you plan to use that data later it can add a good number of tables to your software.