Earlier quoted context omitted.
>If they can't produce enough value to justify minimum wages There are alternative views on this. Marx's theory for example says that workers are not paid according to the value they create, or what their labour creates, rather they are paid at the rate which is required to sustain them. The commodity which the worker produces and sells is termed 'labour power', requiring among other things food, enough to support a…
Marx is trivially easy to refute. Try this exercise: See how far you're going to get with your startup by offering to pay software engineers "enough to sustain them". This is cartoonish. I can't believe people say stuff like this in the 21st century.
This is not a refutation. Just like the raw materials used for production, the means of production, land rent etc. what is purchased is a commodity. Labour-time is that commodity. It makes good business sense to not only buy commodities at their value (and no more) but even to try and buy commodities under their value.
Why do you think labour-power is any different? It must be paid in accordance with its value, and how much extra is minimally required to ensure the continuance of the production of this commodity.
>The owner of labour-power is mortal. If then his appearance in the market is to be continuous, and the continuous conversion of money into capital assumes this, the seller of labour-power must perpetuate himself, "in the way that every living individual perpetuates himself, by procreation." The labour-power withdrawn from the market by wear and tear and death, must be continually replaced by, at the very least, an equal amount of fresh labour-power. Hence the sum of the means of subsistence necessary for the production of labour-power must include the means necessary for the labourer's substitutes, i.e., his children, in order that this race of peculiar commodity-owners may perpetuate its appearance in the market.
>Included in the value of labour power is both a physical component (the minimum physical requirements for a healthy worker) and a moral-historical component (the satisfaction of needs beyond the physical minimum which have become an established part of the lifestyle of the average worker). The value of labour power is thus a historical norm, which is the outcome of a combination of factors: productivity; the supply and demand for labour; the assertion of human needs; the costs of acquiring skills; state laws stipulating minimum or maximum wages, the balance of power between social classes, etc.
If the capitalist paid for labour-power at more than its value consistently, in the long run the capitalist will tend to make no profit at all. Profit originates in surplus value being extracted, and although there is leeway (there is a rate of surplus value, for example 0.6, though it could be 0.3 and the capitalist would still make a profit) any sensible capitalist will aim for the largest extraction possible.