@didiendninja, the first stage of Gutenberg isn’t about competing with page builders. The page building part comes in the next stage when Customization steps in.
In short, the solution is needed to be accessible to all users. Visual composer isn’t and page builders require another plugin. This is a step for users. WordPress needs to compete and thrive for the next 5-10 years. To do this, as a product it has offer the functionality users expect.
If you look at Squarespace and Wix, they have this and WordPress needs a plugin to even do that basics. Users expect to be able to do this. Gutenberg is the start of the foundation change in WordPress, to move it forward.
Ultimately this isn’t about competing as much as meeting user expectations. It’s easy to see your users and think that is all is needed. WordPress has always been accessible to a wide range of users, over time this is narrowing with complex tools and builders. Things that require learning code aren’t accessible. Developers also want to be able to use the latest languages. Gutenberg sets them also on this path.
It’s important to not see this as competing, that’s not what is the premise. This is about moving WordPress forward and continuing it’s growth as a product.