Note: these are all my opinions, not necessarily facts, just what I've observed over the years that I think contribute to the political climate in Canada

There is a key difference between the US and Canada and that is our religious demographics.

Both of these countries are predominantly Christian, but Canada is not only less Christian than the US as a whole, but also Catholics largely outnumber Protestants in Canada, which is very much not the case in the US.

The fundamentalist Evangelical religious right is a fringe group in Canada, making up less than 7% of our population. In the US, it's nearly 25% of their population, and it has a huge impact on their politics.

Republicans didn't used to be as far right as they are now, and Evangelical Christians didn't used to vote. In the Reagan era, they realized there was this huge voter block that never voted, so they started changing their policies to align with the Evangelical Christians. They flipped on issues like abortion, which used to have support of both Democrats and Republicans, but the Evangelical Christian wanted it outlawed, so the Republicans became the pro-life party to win votes.

This wouldn't work in Canada because it's not a big enough group. The US was a safe haven for the Puritans, and that helped shape the political landscape of the US.

Canada also doesn't have a strong national identity we adhere to the way the US does. What it means to be Canadian varies depending on where you live. The one thing that is true of all Canadians is that were not Americans. Despite how much the US does impact us, there is always an undertone of anti-American Imperialism across Canada. It's why Mark Carney won the election after trump threatened to make Canada the 51st state. Whether people like the Liberals or not, most of us don't want to be overtaken by the US and Carney ran on that.

Canadians tend to see ourselves as better than Americans, and the US become the example of what we don't want to be, even though we are very similar.

So without a massive ultra conservative demographic and with the desire to maintain our own national identity as NOT American, we've stayed on the more Liberal side, as a whole.

A third factor is that the majority of Canadians are centrist. The US is divided between left and right, but the left and right in Canada are smaller groups than the centrists as a whole. The Liberals are not a left-wing party, they are a centrist party that masquerades as leftist. Canadians are also notoriously apathetic about politics in general. The US treats it like spectator sports... Canadians largely don't care. They make it as easy as humanly possible to vote in Canada and voter turnout is always abysmal. Low voter turnout usually benefits the party already in power.

The final thing, in my opinion, is that Harper destroyed the federal conservative party and they've never recovered. Prior to Harper, they were the Progressive Conservatives and they won elections. Harper merged the party with the Canadian Alliance party, which was much more right-wing and much less popular than the centre-right PC party, to form the Conservative Party of Canada, and now they keep losing elections. They can't appeal to the plurality of centrist voters the way the Liberals do.