Why is embedded help not popular?

I’m wondering why modern help systems are more passive than active? For example, each good guide through something look like this:
So why we don’t see this directly on website (service provider), but have to search for an…
UI/UX Design Patterns: What are good examples of registration flows that require a lot of info but manage to make it a painless experience?

When Twitter redesigned their sign up process with the goal of increasing user engagement, they actually added a screen / step. But, that actually helped them and they said the experienced a 29% increase in growth. It’s articulated very well in this article: http://www.lukew.com/ff/e
The key is to break up the sign up / process into logical steps for the user, keeping in mind that if you can show the user the result of their action, then they’re much more likely to keep going. People love feedback – show it to them.
What are the little arrows called that hide additional details?

In UI design, sometimes settings are hidden behind a little arrow or “+” symbol. When the user clicks on it, the item expands to show additional details.
Does this UI pattern have a name? Other than “little arrow”?
For ex…