How long until the USA retreats back into isolation with a few selected allies?

I think in 50-100 years the USA will voluntary or maybe involuntary retreat back to pre-WW2 isolationism with a few allies. First off I think the allies that we would have would be Singapore, Taiwan, Israel, South Korea, and maybe the UK and Japan. I think America will still be the dominate power in the world, but I feel like by then the American populace will want the USA to focus on more domestic views. In other terms the USA would be the ''sleeping giant'' of the world. Unless someone can convince me other wise I can't see why this isn't the future for the USA