When discussing liberalism in the context of liberalism vs Leftism, they are faily opposite. Liberalism desires Capitalism, perhaps with some tweaks or larger safety nets, while leftists seek to end Capitalism and pursue Socialism of some form. This isn't "75%" of the same views at all, liberalism is fundamentally entirely incompatible with Leftism just like fascism is incompatible with leftism.

Additionally, in the West, Leftists have not been the deciding factor in elections, liberals have, be they more conservative or more progressive liberals.