Literally just left a really enjoyable job with a Toronto company for a California company that pays 50% more. This is completely correct.
The work is remote, I still live in the same place, but I've increased my income by 3x, I don't see how I could justify staying with a Canadian company.
The kicker though is that presumably many Canadians harbour some type of fantasy in their heads of moving back home after N years, at which point the conversion of USD back to CAD can tip the balance. Historically the USD has been worth more than CAD, except for two times in 1974 and 2007.
It gets worse because Canadians that come down for "just a few years" probably end up staying longer since the original logic that drew us down in the first place is likely still valid. Throw on top the overhead and friction of uprooting your settled life (friends and maybe kids) and then it becomes even tougher to go back.
Next thing you know, you're applying for a greencard and the rest is history.
Rent is certainly higher in the Bay Area, though less higher now vs. a year ago, and even so, at the income levels we're talking here (especially if going to FAANG or a unicorn), there is very little chance you'll end up with less disposable income after rent and health care.
If you want to buy a property, you have your work cut out for you since real estate is insanely expensive, though. It's not too hard if you're a dual-income high earner couple but very hard otherwise and will take a number of years of savings. This is worse than the Vancouver/Toronto housing markets, but it's less worse than you think given how crazy they are now.