In late 19th century ketchup category only had brands which are carcinogenic, same as today’s cigarette category. Henry J. Heinz, the founder of Heinz, saw a potential to beat the competition by producing a ketchup which was not carcinogenic. For almost two decades Heinz researched how to make a safe ketchup and finally succeeded in 1904. This established Heinz long term leadership. Read more here.
Heinz history is a great example of category stability which resulted in clear brand strategy. If the category was unstable, if it was disrupted often, it would be impossible for Heinz to define and build a decades long brand strategy. Some industries or categories are disrupted only with long term strategies, while some are unstable and are often disrupted. The most common disruption factor is technology which not only influences the product, but also content and media.