If you have a skill that's rare enough and wanted enough, you can definitely pull on the rope at least a bit.

A friend of mine is the IT guy in a medium business, they are two doing very specific tasks they've trained for years and that makes them hardly replaceable. He wanted more homeoffice but they kept denying him and ...didn't behave as the best bosses for him. So he openly told he wanted to leave and started acting more freely in the business. Learning that he might be alone, his pal quickly took notice and changed job faster than my friend. Fearing having no IT guy anymore and their precious knowledge, his boss convocated him, and asked him what he wanted for salary. He used towin around 35k, which is already really good. He asked 48k as a joke. The boss wrote down 50k.
Sometimes you DO have the power.