It also has to do with how much easier it is for humans to imagine binaries, I think. In the socialism/liberalism/conservatism trifecta, all three ideologies have reasons for conflicting with each other. However, when any one of them loses traction (for whatever reason), it is haphazardly mashed together with one of the remaining ones. In the long run this leads to conflicting views of what the mashed together block is really about, especially as the forgotten part gets rejuvenated. In the US, this is about ”leftists” breaking out of ”liberalists”, with confused conservative onlookers. In Sweden it’s about a conservative upswing breaking apart the ”right”
Traditionally, Sweden has had a socialist (led by the Social Democrats(S)) block and a conservative/liberal block, with a focus on the (economically) liberal during the last decennia. However, as a new conservative party, the Sweden Democrats(SD) popped up, and S slowly drifting in the liberal direction, the old blocks collapsed and new ones are being formed. The government is still formed by S (and the tiny Green Party), but now backed up by the liberal half of the ”right-wing” block. Against them, a conservative block is being formed by the conservative remainder of the ”right-wing” block, and SD. In the opposition there is also the socialist Left Party. I find this interesting in oh so many ways, but the most interesting one might be that SD calls all non-conservative parties ”left(ist)-liberals”. I think the stance might make block-forming easier.