This entire post hinges on the fact that you have an above average income. The fact is that if you are poor in the US, you are fucked. I am also a dual citizen (Ireland/Canada) and now, at 37 years old have lived almost exactly 1/3 of my life in Canada, 1/3 in the US, and 1/3 in Ireland. In all of those places I have moved around a lot - from Vancouver to Toronto, from Phoenix to Boston, from Dublin to Limerick and all kinds of points in between.
The United States is a country worth visiting, but if you can't afford to pay for one accidental hospital visit, one bout with cancer, one illness that you haven't predicted you will lose everything. The education system sucks unless you can pay for private school. The country is deeply divided across so many different lines, most notably the divide between rich and poor.
What you call optimism is often just delusion about the reality that not everyone who works hard will 'make it'. For every salary that is higher in the US, there is also one that is lower - you mention software developer, but what about the waiters?
The United States is a country in which individual liberty to do what the fuck you want is held to be more valuable than the greater good. The definition of a society is a group of people who agree to compromise their own absolute freedom in order to guarantee a higher quality of life for the group as a whole and the United States falls sadly short on that score.
There is no safety in the United States. There is no guarantee that you won't fall through the cracks.
You say the United States has culture and of course it does - but that culture comes at a price too. Only the rich are ever really involved in the loftier cultural spheres in the United States. For the vast majority it's beer and baseball and lowest common denominator television. Sure there are exceptions, but we can't measure a society in general by the exceptions.
You talk about 'tall poppy' syndrome and I understand what you mean. Ireland is terrible for it. But so is the United States. Try to be even a little high minded and you will be called a snob. Talk to any average person about those cultural institutions you mention and they'll give you a yawn and an eye roll.
Drinking culture in the UK and Ireland can't be used as an example of what's bad about Europe. The fact is that Ireland and the UK are about as European as Mexico is. These are the outliers. Germany, France, Italy, Belgium, Denmark, Sweden... Those places are much more sensible and are much better representatives of Europe.
I have not lived my life perfectly and as a result I have had wildly erratic fortunes - I have been reasonably well-to-do and I have been homeless in both the US and in Ireland. You know what I've never had to do in Ireland? Sleep in a fucking doorway on the street in the snow. You know what else has never happened? I have never gotten 3000 dollars worth of a hospital bill for a five minute shot and prescription at the hospital because I had to leave a bronchial infection so long due to the fact that I couldn't afford insurance.
This sub may, in fact, be guilty of a case of 'grass is greener' but you're looking at the US through your expensive rose-tinted glasses. You clearly have money enough that you have never had to experience the hardships that the US can force on you. Yet.
Get back to us when you have some experience actually living on both sides of the fence.