Of course you can quit. The power imbalance is mitigated in other countries by making it hard to terminate without cause and on the other side you will have to give more notice when you quit. In Germany when I lived there it wasn't uncommon to have a contract that let you quit your job with 3 months notice or even 3 months from the beginning of the next quarter, things like that. Sure that's inconvenient for some but it's a good trade-off for others.