Do You Have a Brand Proposition? Is It the Same Journey?

When a brand knows who it is, how it sees the world, it then goes find people who see the world the way they do. And now the brand should go preach the gospel to those people. These were brands that started out with arguably visionary individuals who were almost startups. How much more difficult is it to sort of transition from a traditional brand proposition or a product proposition based brand when you're already established?