Why don't other SaaS companies follow this example?

This is EXACTLY what all headers should do (it also on my free cheatsheet)👇

Introduce what the product does right at the top of the page! Give them a hint of what it does and the main benefit.

It has to answer "What's in it for me?" as fast as possible and Quokka does this pretty well.

Take notes and explain your product just as simply and as soon as this example.