The US Supreme Court decided many decades ago that the Bill of Rights doesn’t apply wholesale to the states. Instead they held that each right has to be analyzed separately to determine if it should apply to the states. This principle is called “selective incorporation”.

At this point most of the rights have been incorporated and only a few have specifically not been incorporated, most notably the right to a grand jury indictment. The excessive fines clause was one of the stragglers that hadn’t been decided either way. (The third amendment probably never will be decided.)