It seems to me that even in the beta the costs were increasing, and then they increased them even more after the change.
Since materials have to be farmed and not obtained simply by exploring well, the projects have always been a bit strange, in Ori and the Will of The Wisps there was a key item for the projects and the progression was much more beautiful and satisfying.
It’s strange how clay granite and salt stone become literally useless after you finish the projects.
In my opinion it makes no sense to use iron and wood both to strengthen weapons and to build projects and now that the costs have increased it is even more evident as problem, I talk about it here: The Crafting Materials are an Unintuitive Mess.