To go back just for a bit is too disruptive - I have NO desire to ever have to uproot like that again and we're quite settled. Also we don't want kids and to have Europe in our backyard for travel is too good to let go!!!
That's all part of our decision as well! I completely uprooted myself once - moving from Kansas to Florida, then again to move here. Enough! And we love traveling Europe.
From what DH has seen of life in the US (on visits when we were dating & since), he thinks it's really not for him. He likes urban/suburban life, but where I lived & the places we go to visit - that means sitting in a car in traffic for hours & hours & hours on end. He absolutely hates that with a passion & so do I. Other than in relatively few large metropolitan areas, good public transport doesn't really exist. (The country is just too enormous!) He doesn't like that the country really isn't set up for walkers - very few public footpaths, open access to countryside, etc (as compared to here). When visiting my mom, we thought we'd walk (less than 1 mile) to go out for supper - but it means taking your life in your hands, crossing busy highways (with no crosswalks!) just to get to the restaurants.
Then there are all the other annoyances - conservative politics (Dubya), right wing religion in your face at every turn, no national health care system, and a number of other things but I'll stop lest I get people all stirred up. We most likely won't be having any children, but if we ever did - I'd sooner bring them up here than I ever would in the US.
A lot of these things are largely subjective, I realise - considering where a person came from or lived in the US, and where they are living in the UK. I missed Tampa a lot when I moved here, but mostly for the weather & little else. The grass for me is definitely a lot greener over here!