Like all other creators of intellectual property, such as architects, designers, illustrators, musicians, painters, performers, sculptors, software engineers and writers, a photographer can (and must) control the use of their work. This is called “copyright”.
If a photographer loses the copyright to their images, they lose not only the use of those pictures but also all future income from them. Loss of future income equals loss of business success.
Maintaining copyright is not about artistic ego. It is about business survival and, hopefully, profitability, for which all businesses strive. Simply put, a photographer who doesn't care about their copyright is not a professional.
A professional photographer will be happy to license any right that the client may need. Afterall, the more rights granted, the more revenue the photographer can generate. A client need only discuss what rights they require.

Sometimes a client will ask for “all rights”, “complete buyout” or “copyright ownership”. This is always very expensive, as all rights include such things as: editorial rights in all countries for all eternity; advertising use in all media in all countries; worldwide TV broadcast rights; book publishing rights in all languages; product rights for such things as calendars, posters, coffee mugs, mouse pads and T-shirts; resale and sub-licensing rights.
Very rarely, if ever, would a client really need to own all copyrights to any image.
As a general rule, we maintain copyright ownership in all our photographs. This includes the right to use any photograph for our self-promotion and, if applicable, editorial resales. Nevertheless, just so you know, for copyright ownership, our minimum surcharge is +100%.