What an amazing point!!! You've pointed out that Marx's 'means of production' were a idealized simplistic definition. Anything involved in the production process is a means of production. And having access to another's time is exactly what Deathy is decrying.
It's interesting that in a economy that Deathy describes as "capitalist" (whatever that means) he describes the 'unsweated-for" profits of capitalists as "exploitation". Yet, under what he describes as a "socialist" society a person who is physically incapable of working and yet partakes in the social product is not "exploiting" the workers. This does not follow and displays the whole force of Deathy's arguements as the moralizign it really is.
I am not denying moralizing as I do it as well. However, the whole Marxist historical dialectic was expressly for the purpose of avoiding simply applying morality to economics. Stuck in all their verbiage and theories Marx, and Deathy, are just applying their moral outlooks to an economic analysis.