>Where are the long-term immigrants --typically with spouses and children-- talking only about the positives?

Here. I'm an immigrant to the UK. I've been here 20 years. I love it here, except for the weather, which I miss from my home country.

I do miss a lot of other things, but all in all I've made my life in the UK and settled here with children.

I think I'm one of many, many millions of people globally who have done this and speak positively. I'm not sure why that seems far fetched to you?