This is not a useful definition of “taking advantage of”. I don’t see anyone clamoring to pay anything more than the lowest prices at Walmart or Target or Amazon, nor are they offering to accept less than the most their employer or customer offers them.
If there is a power imbalance between buyer and seller, that is the responsibility of the government to remedy. In your examples, options would be UBI for people who “need” to drive for Uber, and taxpayer funded research to develop medicine so that they aren’t patented by a private for profit entity.