In 20 minutes I have about 150 mbs. There must be some way this can go faster

Where are you exporting it from?

SSMS Data tier export. However it finished just after I sent that message. Bacpac file only takes 150mb compared to the size of the tables, but I don't know how a bacpac file is structured

A bacpac is a zip file containing the schema and all the data in the database (change your file extension to .zip, and have a look inside), but it's zipped at the *receiving * end! sqlpackage copies everything from the database using TSQL (and using your server's resources). So it takes as long as it takes to send all of the data in your database, row by row, to wherever you're running SMSS/sqlpackage... is that's a big database, on a slow network and/or low powered server, it's going to take a while.

Ah, good to know. Thanks!

Could be revisions of content nodes. Every time you publish something, a copy of the node is created in the database

Yes, so an older site is likely to have had more publishes in its lifetime. Also depends a bit the schema. Nested content and the grid (and blocks in newer sites) store content in big blobs of JSON - a single character change anywhere in the grid gets a whole new blob of JSON saved to the DB. These can get pretty huge, I've recently inherited a couple of >10GB sites - they're not that big, they just really overuse the grid.

Im pretty sure this uses the grid so that can certainly be it. The more you know!