Because for profit publishers want more profits.

Some countries are now passing laws to make publicly funded research free, but for now if open access is not available use sci-hub, unpaywall, r/scholar or even email the author directly (many will respond with a pdf of their work). Your taxes have already paid for the research in many cases and the fees do not go to the researchers or the peer reviewers, they just go to publishing companies like Elsevier who add essentially no value.