I consider it's true. Specially in products it's hard to develope such as soaps, detergents,... Every year we have products that wash cleaner than others... It's impossible. But we believe the clean better.
I think it depends on the product. Most products need to be updated and improved annually to keep up with the competition.
Others, all they need to do is keep the same design/model but just change their brochures/leaflets show/focusing on another aspect of the product that would somehow appear new in the market although no changes were made on the actual product.