Canada has a more common sense policy then the US and doesn't get hung up on extreme ideas. We don't see every new social program as a gateway to Communism, we don't see banning military style weapons as a gift to criminals, and we don't see banning racist posts as an attack on free speech. If there were a true slippery slope it would have happened already here. Instead, we got a better country out of the deal. Less violent crime and murders, less racial tension, better social programs, less poverty, longer life expectancies, better education standards, ... .
It's like I said before, the US does business well. Canada is slowly incorporating some of that. You don't do some of the other things very well and it has clear negative impact on many American's quality of life. Even some doing extremely well are only one bad adverse event from losing that ( eg a health crisis, getting caught in a shooting ). Canada is in no way perfect ( eg out gun controls don't go far enough ), but we are doing it better in Canada. At some point more income becomes less important then the other stuff. If enough of the country is losing, bad things can happen.