I'm sure it wasn't common, but even in such a company you could "extract as much money from the clients as possible" by delivering as much value as possible. Doing things carefully, solving problems, going a little above and beyond what was expected to the point that your clients were glad to pay your billings.

Also, it's just two sides of a point of view to see something like "upselling" as pressuring clients into buying things they don't need, or making them aware of things they didn't know you could provide.