That is *NOT* always the best course of action. Knowing how to, and knowing when to do non-linear item building is a part of being good at this game. Sometimes, its ok to build Chalice early and then let it sit for a while, so you can prioritize other items.
(Ryze sees a lot more of this than other mages, what with Tear and Catalyst both being really good on him early game, but with AA Staff/BV/RoA not being hugely important rush items.).