Why is the jacuzzi called a jacuzzi?

Jacuzzi is a brand name, not a generic term for a hot tub. The company Jacuzzi invented the first hot tub in 1968 which used jets to release heated air through the water causing bubbling action, it was initially designed for hydrotherapy treatment to help relieve pain resulting from rheumatoid arthritis for Roy Jacuzzi's seven-year-old son Ken who was born with the debilitating disease

Jacuzzi became the standard and generic household name because their product was the main brand to advertise in television and print while no other competitors advertised as much back then