Perhaps with some difficulty! :)
The dictionary (Merriam-Webster) says:
deserve: ‘to be worthy, fit, or suitable for some reward or requital’
..but that seems fairly vague.
One might say you ‘deserve’ something if you have done a creditable thing, for which the fair reward would be that ‘something.’
Each of us, of course, may have our own ideas of what is or isn’t ethical and ‘fair.’ And, personally, I would argue that was is fair will depend on what you are going to do with the ‘something’ in question.
My point, however, is that the consumers and employers and others that constitute ‘the market’ are rarely even attempting to judge what is ‘fair.’ They’re just concerned with paying as little as possible to get what they’re after. Thus, the market as a whole is not really even attempting to be fair.