Salaries are one part a maintenance fee to keep the worker able to work and one part based in supply and demand. It's not "how much rich people like you", rather it is "how can you be kept working for us" (the requirement of which depends on industry and how much training is required. For example, logistics and food have a very high churn whereas white collar jobs can take longer to get a worker generating surplus value so they are paid more), and "how difficult is it to hire someone here" (which is why lawyers and doctors are highly paid as there is a high supply and a low demand). How wages are determined is discussed in depth by Marx, among other scholars.