there are "institutions" that have that "oversight" over bitcoin. it just happens that they are plural instead of being 1 centralized "institute" controlling everything. and they are called full verifying nodes. at the heart of it, the concept is the same. these nodes are doing the verification and in short enforcing the rules just as 1 governing body would do in a centralized system.
But what if that group of full verifying nodes "gets into the hands" of some institution that aims to enforce the rules? In that case that institution would effectively have said powers. Whether this is an official institution or a non-official group of people, I believe this has happened already in the crypto space before, right?