[byw]

My impression with the visa situation is that while technically green card is very difficult, in practice most expats have no issue renewing their work visas, so effectively living as long term residents - buying properties, getting married, and sending their kids to (mostly international) schools. I've also seen quite a few who worked for a few years and then started their own businesses.

In terms of how well expats integrate, I've seen people from across the spectrum. There are definitely those who are meshed into the local social circles. Foreigner privilege is a thing, and I find that how you view social status is a strong determinant in how well you integrate. Those with a more egalitarian mindset seem to do well in this regard.