So which countries are you talking about?? Theoretically you cant get more developed countries than Western Europe and Scandinavia, especially Scandinavia, rich Arabian countries are still developing.
We are from UK ourselves, the bottom line is that for our professions there is larger pool of work and better pay in USA and even if we got our pay equivalent in US dollars to our pounds, we could lead a slightly better life-style due to the fact that your property prices are much much cheaper, fuel, cars... If you are a young driver you dont have to pay insurance worth 3 times of the car just for 1 year and sometimes it can even be up to x10 times.
We have great social security, our NHS is "free" I mean we do have to pay it out of our income with no choice, but at the end of the day no one will ask you for a credit card in the hospital or at GP`s. Problem is that, if you are not on death-bed they dont do anything and many are forced to buy private insurances.
UK social security is so great that some unemployed immigrant families that dont speak english but have 10 kids live in central London next to richest people in the UK or maybe the world, with houses in the neighborhood going for about 20-30m pounds, great if you are a benefitter, bad if you have to pay for this, while working full time and living in some tiny house on the edge of London.
Our public transport prices are ridiculous, we have to pay nearly 30 pounds a week for a bus pass that goes 10 miles outside of the city... Still seen as a good value since single cost around 5.40. Still not as bad as dishing out 30 euros in low end Pub in Sweden for a Pint and small meal for 1.
The whole atmosphere is very depressing, the houses in UK are ugly and all grey "to preserve character" coupled with fog,rain and drizzle gives a truly great atmosphere. No wonder so many UK expats in Spain just leaving uk to actually get some cheeriness in their life. Every time we can, we always book a holiday to the Mediterranean or somewhere else sunny to get away from this "character" at first we thought we were the only ones, but pretty much every hotel we went was full of Britons or Germans.
Overall the reason we are looking to go to the USA is just because we are not English born and its just hard to live here and deal with the English way of life, we see it as degrading and depressing, true fact is that we dont know whether USA will be even worse because it will probably take 5 years to understand, but maybe once we understand that USA is bad place to live we will come back to Europe with big smiles on our faces.
Another reason we dont mind going to the usa is that we are experienced Immigrants who pretty much dont have a "home" we have nothing to loose. If I could go back 10 years when we moved to UK, I wouldnt do it. But now, no more damage can be done to us, so why not explore something in this life, while its not too late?
We never applied for GC to win, it was our first time and just for a bit of fun, now that we got this opportunity it would be wrong not to take it and end up living in regrets.