How long will it take to replace these employees with machines/robots?

Robot Fast Food and Quickie Kiosks have been tried before. They never have caught on. Although I am a Geek, I understand the unique aspects that actually make the application damn near impossible. No, we will hear the Doom and Gloom sayers talking about the end of the world if Fast Food Workers can come off Public Assistance. From looking at Europe and Australia. They will eventually make an adequate wage and OMG I'll have to pay a quarter extra for my Big Mac. I'm not going to lose a lot of sleep over it.

I predict ordering kiosks in fast food places will be ubiquitous within two years.
Then watch the same folks rail against the evil corporations...

SSgt Alex Robinson - Not long. The establishments will either close or automate.