I think this is absolutely true for user to user social interaction websites, less true for B2B applications. In the last 2 years at my company we took an old e

I think this is absolutely true for user to user social interaction websites, less true for B2B applications. In the last 2 years at my company we took an old early 2000s looking application that our customers used and completely redesigned it plus brought in a lot of new functionality. To the point where at the core they are still getting some of the same job done but with such a different experience drawing 1:1 lines between the functionality is blurred. This whole new experience has been absolutely fantastic, our customers rave about it and our revenue has grown around 250%. Not to say this is always the case but when something is dated and not providing the experience it can/should be, sometimes a rewrite can be a huge win. But like you said, it still can't be done in a bubble and it can't be driven by a vision of a designer but ultimately the experience your customers seek.