Mind, salaries often tend to be indexed to the local cost of living. So you could have a pretty decent standard of living even if your nominal salary is a bit lower.
Canada (in my case, specifically UBC) has piss low grad student stipends, even relative to local CoL. I was making full time minimum wage as an undergrad researcher, and my PI told me that he was still paying me more than his PhD students (2500/mo for me vs. 2000/mo). I dunno how someone could live in Vancouver on that salary without savings or additional scholarships
Wages are about half of the US yet in places like Toronto the COL is super high.
These profs likely negotiated a fat payday. It happens all the time - profs move from Harvard, Stanford, Yale to less prestigious schools because they’ll get something they otherwise can’t get - tenure, head of a school, more money, whatever.
Considering this move would have taken months to negotiate it likely has nothing to do with politics at all.