So people just access Google Now in one of the three other ways.
Don't you think that statement is a little pedantic?
No, because you're taking it at face value rather than the meaning behind the statement.
It's not the fact that not being able to access Google Now in that manner is the problem, it's the fact that some features can only be included by updating the OS (unless Google finds a way of making it even more modular/extensible than it is now).
There will be other features in the future, and there has already been many, features that can only be added/improved by updating the OS.