This idea can sort of already be done by having, say, a 1 Blue Door with 4 copies. You need 4 Blue Keys to get past it, but you spend 1 Blue Key at a time. There are already a few levels that have doors that start with an amount of copies other than 1, so this can already be accomplished. The only ways your idea differs from this implementation of it are that the implementation is slower (since each key has to be destroyed individually) and how these partial doors would interact with mechanics like Master Keys (of all signs) and (ROT13) Tyvgpu Xrlf.