I think this is the bit a lot of people miss. Many many of the Irish immigrants to America didn’t go simply because they wanted to. If they could have they’d have preferred to stay with their family and live in Ireland, but economics made people move.
No-one would, I hope, be dismissive of the children or grandchildren of current economic migrants or refugees still feeling at least partly Pakistani/Kenyan/Syrian/Chinese. It’s basically the same thing, just more years down the line.
And this isn't a historic thing, it's very much been happening in my lifetime, and I'm in my 40s. The 1970s and 80s were periods of huge recession, political corruption and mass unemployment in Ireland the 80s in particular were one of the bleakest periods in its recent history, with a succession of weak, unstable and short-lived governments, an overinflated currency, massive governmental borrowing by the late 80s, the national debt was something like 130% of GNP. There was high unemployment, falling standards of living, huge emigration.
I started university in 1990, and my generation of school leavers knew that we would have to leave Ireland to find work. Traditionally Ireland had transported its unskilled and lowskilled workforce -- in the 80s, that now included the highly-skilled and educated.
When I went to the US first myself, before I got a visa in the Morrison visa lottery, I stayed with older friends who were among the hundreds of thousands of undocumented Irish -- they both worked but were often on the breadline, and had no health insurance or safety net if anything went wrong. When I was staying with them, D was walking to his construction job along the hard shoulder of a major road because his van broke down and they didn't have the spare cash to repair it. When A fell down stairs and broke her leg around the same time, she was driven around in an ambulance to several hospitals before one would admit someone with no health insurance, and they couldn't come home for family funerals or emergencies because they couldn't risk not getting back in.
It was a frightening and precarious way to live, and I think clinging to the cooperation and shared interests of the Irish communities were a psychological lifeline (and a source of actual help when needed). And the saddest bit was that eventually, they decided to return to Ireland when D had a nervous breakdown, and only lasted a couple of years -- they'd been away too long, and it wasn't as they remembered. They went back, this time documented, and have had children.