Ever since the Reagan/Thatcher revolution there haven't been too many pay rises for the working class. Everything that could be outsourced and offshored was outsourced and offshored. In Europe they have been continually expanding the EU so this process has been more 'moving East' than moving offshore.
Meanwhile, the rentier class has expanded on the back of cheap money and a whole new class of service jobs has arrived to suit the rentier class, for example car detailing, yoga instruction, property management, food delivery and dog walking.
The rentier class don't add value, they are parasites, plain and simple. They have got richer, for sure, but the price of this has been everyone else priced out of their own homes and communities. This rampant house price inflation is ridiculous, hence stagnant pay just doesn't go as far, even if manufactured goods are cheaper than they were before the Reagan/Thatcher revolution.
Hence my problem with the 'scientific' paper. It has nothing to do with immigrants, more to do with not believing people are better off.
Speaking personally, I only got into software development because my customer service job was outsourced to India. Yes I did get a boost to my salary, and yes I did have to reskill to achieve that when I could have happily bumbled along being nice to people on the phone all day doing customer service. However, that only got me back to the start, with a wage that, accounting for inflation, was less than what I was getting as a student during my 'year in industry'. Furthermore, I was still just sat at a desk with a screen, just typing different keystrokes.
I have always been welcoming to whomever arrives from wherever, however, I always feel bad for those that have had to move due to war, which our Western governments are invariably complicit in.