So, basic question here: why do you want to call RPGs storytelling?
Classifying RPGs a storytelling vs something else is basically a semantic dispute, but it's semantics with consequences. Specifically, it usually has one or more of the following purposes:
- Encouraging the use of methods developed for one thing to the other.
- Sharing of prestige.
My feeling is that methods intended for storytelling should be used carefully for RPGs, with an eye towards the differences, which encourages keeping a bit of separation, but I could possibly be persuaded otherwise.