My impression is that we in Canada are more centred around the authority of the central party organization than most Westminster democracies, more centred on party structure.
In my view, it is not a criticism of party leaders for being hogs for power over the years, but a reality that our parties, with rare exceptions, are focused around the parliamentary leadership and relatively few people outside, and don't have a broad membership that influences the party leadership. A lot of what we see going on in representation reflects the almost amorphous nature of the support for parties and candidates in constituencies—and across the country, of course.