Honestly, I disagree with this. Iteration is great for developers, but not users. To use your tool analogy, users are attempting to use the toolbox you made to perform a task, but the content of the toolbox and how you use it changes every day. Users of the toolbox can never become expert users, because they can't ever rely on their past experience with these tools - the usage has probably changed in subtle ways.

Personally, I really hate having to re-learn how to use a screwdriver (or a blogging platform) every few days - and I'm a professional tool builder myself! It sucks even worse when I can't use your screwdriver if I only have 3G internet access.