Yes, they should be able to and
contrary to popular belief, most of them do with the help of government assistance such as SNAP, temporary assistance, subsidized housing, Section 8, etc .
People working jobs like McDonald's, Burger King, and most fast food
restaurants/food service are eligible for those aforementioned programs and assistance.
Could they live off those checks alone, maybe but
unlikely without the help of assistance.
See jobs like McDonald's and fast food jobs in general are supposed to be entry level jobs (think cashier, customer service, etc type jobs), meaning when you're young (teens to early-mid 20s) and just looking to get a taste of what employment feels like, similar to being a cashier or grocery store stocker and move on to something better in the work field whether it be in the food industry or elsewhere, you're not supposed to make a career of it unless planing to become a manger or owner of a franchise.
The issue is that most people in this country don't have the necessary skills to improve themselves which is why you'll see people in their 30s and 40s working Burger King (it's not their fault) when they should've been moved onto working something better in the food service industry.