I think that gets the causality the wrong way around. I've heard plenty of people express similar sentiments without (so far as I can tell) being Marxists.
More likely: it sticks around as a tenet of Marxism because it's a thing many people find intuitively plausible. "I did all this hard work, so I should be rewarded" is a pretty natural thing to think.
> "I did all this hard work, so I should be rewarded" is a pretty natural thing to think.
Is it really? I rolled a boulder up and down a hill all day, pay me.
"Nobody asked you to do that and nothing productive was accomplished. Nobody will pay you for that."
But I worked really hard! Labor creates value, therefore I am entitled to payment.
Whether you're rolling a boulder or writing a book, your labor hasn't created value unless you've actually produced something other people subjectively believe to be valuable. The subjective theory of value is common sense. The labor theory of value is obvious bullshit. It might fool children but for an adult to believe it requires brainwashing.
The miscommunication in that case is that the person doing the boulder-rolling/book-writing/startup-programming genuinely thought they were providing value to society. Your example picks a ridiculous non-valuable labor. To understand their point of view, imagine something that you would consider valuable, but which goes generally unrewarded. To get you started: feeding the hungry, sheltering the homeless, volunteering for a fire department, cleaning an oil spill, rescuing animals, planting trees to reduce man-made erosion, ...
Choosing to write a book that nobody wants to buy is no different from choosing to roll a boulder up a hill. You better be in it for fun because you're not doing anything of value to anybody else.
If you want to volunteer for homeless shelters or something, then you can sleep sound with the knowledge that what you're doing is worth a great deal to people who can't afford to compensate you for it. But writing books nobody wants to buy is not that sort of selfless act of charity.
Read my parent comment. Labor does not equal value by how most people define it. If I can labor for a task that people don't find valuable, like rolling a rock uphill, that means people intuitively feel some sort of subjective theory of value that's not connected simply to how hard someone worked. Hence, LTV does not make sense and we must find a different theory of value. Now, you can disagree that capitalism is not such a theory, but you ought to be able to agree that LTV ain't it, chief.
You haven't said anything about land, only about labor, so your sentence does not follow. You’ve made a case for why labor inputs might not be directly related to market price, but that says exactly zero about land?
Why are you talking about land? This thread is about the labor theory of value, LTV. Are you talking about the land value tax, LVT? Those are two very different things.
More likely: it sticks around as a tenet of Marxism because it's a thing many people find intuitively plausible. "I did all this hard work, so I should be rewarded" is a pretty natural thing to think.