'I have to agree that expat's arguments need to be taken with a pinch of salt.'
Did I imply otherwise? Um, no, I deliberately set out it was hard to explain and that is was my experience and opinion and that there are serious economic issues in many areas.
Did I imply one is better? NO. In fact, I wouldn't live in the US in our present circumstances.
But that's the other thing, Brits are just as defensive about any 'con' a non-native brings up as Yanks are - the apple certainly didn't fall far from the tree in that! Natives are allowed to moan away. It's a moany place. If you moaned like this in many places in teh US, people would tell you to shut up and stop griping or 'Well, you know where the door is! Bye!'
No place is perfect, for my children, though, with their background and upbringing as it is going here, the US is probably going to offer them more opportunities than here.
'I just do not see the whole 'everything is cheaper', especially for an expat who has no credit rating and therefore car insurance 12 times more expensive than the UK for example.'
Because the OP's spouse is American, it's possible he still has well-established credit there, bank accounts, etc.
Not everything is cheaper, no.
But on the whole, many things that are vital are. And, in most places, you get more property for cheaper that is often enough more modern/modernly comfortable.
Food I didn't find cheaper. Utilities, petrol, clothings, many activities, housing were a lot cheaper.
It's when the pros are greater than the cons that you have to decide if it is the right move for you and your family.