Well this is where I need help because I don't consume very much punditry. I read books and articles written by historians, organizers, and activists, and I talk to people.
You have a way of explaining your idea that is a little obtuse. You're posing questions in the negative, and I need explicit and concrete.
I asked what you mean by leftists missed the boat on liberalism. You ask how many leftists begin by describing private property relations as the foundation of their politics. I would say, none, except perhaps to say they reject it. Then you suggest, again in the negative, that leftists use the talking points of "leftist elites", I assume you mean leaders but name no specifics, use talking points from "a hundred years ago" that are ineffective against most regular people's learned conceptions about how things work.
This leads me to believe that you adhere to a definition of liberalism that is similar to a lot of leftists, where you consider all capitalist ideology to be liberal, so progressives are liberal, but also conservative rightists are liberal because they all believe in the classical liberal principle of freedom and progress through ownership of private property.
The second point you make is that leftists aren't doing enough to relate to the masses, and we are stuck in the past with our rhetoric.
Are these accurate assessments of your positions?
Assuming so, I don't think you're saying anything too controversial. I still don't know what boat has been missed re: liberalism. Marx agrees with your second point:
the tradition of all dead generations weighs like a nightmare on the brains of the living. And just as they seem to be occupied with revolutionizing themselves and things, creating something that did not exist before, precisely in such epochs of revolutionary crisis they anxiously conjure up the spirits of the past to their service, borrowing from them names, battle slogans, and costumes in order to present this new scene in world history in time-honored disguise and borrowed language.
And Marx might be an example of an "elite" but he wasn't peddling in narratives. I would argue that the narratives are our own, perhaps based on the work of those who came before. But the success (and failures) of Marx, Lenin, idk name a bunch of ppl, was their ability to understand and act upon their own conditions. However I don't like terms like "dialectical materialism" to describe our analysis, its just so clunky and difficult to understand when the theory itself is a fairly natural combination of concepts people are usually already aware of.
My personal view regarding "liberals" is that often leftists like to use one definition of liberal, the private property one, itself borrowing heavily from Stalinist "social chauvinism" theory, to condemn anyone to our right. I'm not sure if you're condemning per se, but I do think you are subscribed to this very flat theory of liberalism.
The main problem with liberals is their idealism, their inability to distinguish abstract ideas from concrete reality. But this is, as you mentioned in your second point, a problem with the left as well. Also progressive liberals might get a little skittish around maximalist demands like abolish private property, but in my experience they often do not define their own beliefs according to private property relations. We can argue that these relations are implicit in their thinking, but this is another error which causes the left to categorize people rather than convincing them.
Usually progressive liberals define their beliefs as a philosophy that defends human rights and stands up for people who are in harmed, and defends them from the people doing harm. These are leftist principles! There may be structural issues preventing these well meaning progressives from seeing deeper, or affecting change, but their hearts are leftist. And I don't believe that blanket condemnation of liberalism reaches these people any more than quoting Mao at them. I think leftists are often idealist about liberalism, we think of it as a abstract category rather than a historic social relation.