Near as I can tell, a leftist would do anything to keep a liberal out of power over believing only 75% of the same things as them, and allow the right to take control, but at least they get to keep the moral high ground of not allowing a liberal to do that 25%. Never mind that the right actively opposed everything to leftist wants completely.
Liberals are "the right" and they sure as hell don't believe 75% of the same things as leftists. Leftists in the west also don't really have the power to keep liberals out of power, hence why liberals have consistently been the only ones in power for decades. Liberals on the other hand, absolutely do have the power to keep leftists out, and they will go as far as allying with fascists to murder leftists in their beds.
Liberalism is literally and historically where the left begins. The right is authoritarianism and the left is liberalism to anarchism. Liberals are not leftists but it is a signof a distinct lack of education in political philosophy to claim liberalism as a right wing ideology.
Liberalism didn't exist for most of history, so trying to invoke "history" to argue that liberalism has some kind of timeless and eternal claim to being on the left is unconvincing. Yes, liberalism was the left in the eighteenth century, but we're in the twenty first century.
Liberalism is the ideological basis of Capitalism. When Capitalism was a progressive force, ie during the French Revolution, it was considered left wing. Now that Capitalism has become entrenched and turned to Imperialism, the progressive side is undeniably Socialism, while liberalism entrenches the status quo.
Simply saying that liberalism at one point was progressive does not mean history has not had several centuries of shifts and developments since then.
You know, if leberals wanted the support of the leftists, they try something called compromises. But the only compromises they're ready to do is with the fascists unfortunately, which the leftists will never support.
So no, the leftists didn't refuse to make compromises. The liberals did, with the left, because they actually accepted all the compromises with the fascists. And act now surprised that fascism is taking over.
Liberals are spoiled children incapable of taking accountability for their actions.
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.