There's always going to be unskilled jobs, they'll just be different. Especially if America becomes more wealthy in general, there'll be tons of stuff to do for decent bread.
I think more globally than just America, lots of unskilled jobs will vanish, maybe not all, but a lot. new jobs may replace them but they will need be different to today's jobs.
Similar to my thought, many jobs we consider today as skilled, will become unskilled jobs, as they will teach it in schools to everyone. eg It development.