This isn't really accurate. Liberalism and private property rights are fundamentally tied, that was how it historically emerged. Neoliberalism is a subset of liberalism that emphasized privatizing the welfare states that emerged throughout the 20th century as these states ran into crisis of profitability.
The left has opposed liberalism as soon as socialism began to truly take form, especially around the time of Karl Marx and the first international. Saying that the left and progressive liberals want "85% of the same things" is not true at all, the left wants to fundamentally change the entire base of society into a socialist one, not merely expand the welfare state in capitalism, because the main critique from the left is that capitalism itself is unsustainable and incapable of fulfilling the needs of the working class.
Leftists also support revolution over reformism, and do so year-round, every year. It's not that the left gets louder around election season, it's that those that see voting as their sole means of political action tend to notice the left more around election season. This in turn leads to more conversations around reformism vs. revolution, the nature of the capitalist system, and the role of the DNC and GOP in protecting imperialism and capitalism. The US is run by billionaires, it has never been run by the people, because the base structure of society is one where a tiny number of people own and control the means of production and distribution.
