I'm so glad someone brought up the example of Denmark. It's very interesting. Fast food workers there tend to be more unionized as well, which helps them collectively bargain across companies for better pay/benefits.
In the US, companies will say that they can't 'afford' to pay workers much more. But, curiously, they rarely - if ever - make their accounting public. We can get an idea from shareholder reports though what their actual profit margins are. Denmark proves that many companies (especially large ones) can actually afford to pay much higher wages and benefits.
I'm sure McDonald's isn't happy about the strong unions in Denmark, but it's the primary reason why workers there can 'call the bluff' of large corporations and demand more fair pair relative to the revenues these companies make. Although they might not have the profit margins in Denmark that they do in the USA, most companies decide that it's still better to negotiate better compensation packages with the unions and have access to and do business in that market, as opposed to not having a presence there at all.