That's true -- there's just more polarization stateside so maybe its an issue of if Americans can agree on an revolutionary idea, they'd implement it much more rapidly but it's just a matter of getting folks to agree and be on the same page in the first place (though many scholars still think that the American revolution to begin with didn't actually receive the full support of a numerical majority of the populace).I don't think Americans are more afraid of change as a whole. They just can not agree on what change is necessary since the declaration of independence.
Canadians are less polarized politically than Americans and the parliamentary system also makes a difference probably. We accomplished things like single-payer health care and the implementation of the metric system that the US at some point wanted or proposed to do but either stalled or didn't follow through but perhaps the larger scale of country also makes a difference in terms of pragmatism.
Though I do think also even though the narrative is slow, incremental vs. radical, risk-taking change with regard to the two countries, one could argue that some changes/reforms that our nation underwent (the changes led by Tommy Douglas, the Quiet Revolution in Quebec, and Trudeau (the current PM's father)) are arguably the sort that are indeed rapid and revolutionary, not slow and incremental.