I'm going out on a limb here: I think Jerry Hall is marrying for love. I would imagine that Rupert Murdoch enjoys being with her, respects her, doesn't wish she were younger, and seems genuinely happy and delighted every day that he is lucky enough to be with her. Which would all be unusual feelings while dating in one's 50s.
It's illegal for employers to allow the age of their workers to influence decisions about hiring, promotion, and retention. There are laws banning discrimination in the workplace on the basis of age in the U.S. as well as the U.K. However, these laws don't mean that ageism doesn't exist in more subtle ways.