I am no expert in Marx, so I cannot say that's invalid statement, but I do consider labor theory of value wrong and I agree with many of Marxs' views.
Interestingly though, the idea of meritocracy relies on labor theory of value as well. (As someone else above noted: "A large part of the problem for the working classes, according to Marx, is that they buy into the capitalist idea that people are paid what they deserve, rather than what the capitalist can get away with.")
If you believe that capital, or machines, or biological systems, or historical experience, do create value, and not all value comes from the human work, how are you going to split the extra value? Machines don't need it. Anyway you split it, it's not meritocratic, because merit is measured in work.
For example, if I automate something (let's say by happy accident), then I am doing less work now and should deserve less than my previous me, yet at the same time, more value is produced. Meritocracy fails to reconcile this difference unless you ascribe all value that is produced to human labor.