Washington DC didn’t take that power on its own. It didn’t even get it from powerful interests acting on their own. The voters wanted various protections, or what they thought were protections, and they didn’t think the Founders would have opposed federal product safety regulation of interstate commerce.
The voters had nothing to do with it, which is the point you are missing entirely. The Surpeme Court buckled under political pressure from Roosevelt, who sought to pack the Court. The Supreme Court delivered Wickard and several related decisions, which turned commerce power into police power. Thereafter, the decision matrix for the voters was whether a particular excercise of federal police power to regulate commerce was desirable or not. Federal police power was successfully annexed. This happened 100% in Washington DC and the voters were kept complely outside of the decision making process. Congress sat on the sidelines. The Supreme Court executed a coup d'etat limited to the scope of commerce power because they were threatened with packing and were so enamored with 1934 Soviet Russia ans Nazi Germany.