There is no fault here. The FIA has neither the budget or the motivation to create a rule set that stays ahead of the competitors. They would specify sealed spec engines etc. if that was the goal.
Staying ahead of the FIA rules is part of the technical competition in F1. The competitors are well aware that anything new that they develop is subject to banning or copying by other competitors. They are more than happy to get a few races worth of advantage. A whole season of benefit is a real treasure.