Canada tech pay is dramatically lower, at least in FANG in Canada vs. US (or really anywhere in Canada vs. FANG in US). A FANG employee with 6-10 years experience will bring in $300-400k USD in SF/NYC/Seattle. Probably more at FB. Best case is you work for a similar calibre company in Canada and make maybe the equivalent of $200k USD and in Vancouver/Toronto. You still deal with unbelievable cost of living. Your options will be limited to a small number of companies before pay drops off a cliff, so it will be really hard to leave. http://levels.fyi will give you a better idea of how much the Canadian labour market rips workers off. It's no surprise the best we have leave for the US.
You'll get similar vacation, better health care (with deductible/co-pay but you'll save so much from your normal income that the cost won't even matter, along with insurance guaranteed for 18 months after you quit/lose your job if you're in need), and there are quite a large number of these positions in the US. Tiny fraction of them exist in Canada when you consider the number of employers who set up shop here at any meaningful scale. Amazon is one of the few.
A few months ago Canadian media made a big deal about Google expanding its Canadian office space to accommodate "up to" 5000 employees in total. Meanwhile in 2018, they were planning office space for 12000 additional workers. This is in addition to a San Jose campus There is just no comparison in the size of the opportunity.