Commerce in virtually everything runs across national and state lines. You've just bought the argument the beltway bureaucrats want you to - that Washington can regulate anything that can conceivably be bought, sold, or traded in interstate commerce. Don't start bitching that they tell you what kind of light bulbs you have to buy.
Just to put a different slant on this and possibly amuse you. In the last 100 years our large corporations have expanded into every state and into other nations. They have a global reach. Much of this is due to modern communications which get tighter and faster every year. Much is due to ease of modern transport to move what they produce.
Think of the Federal Government as a very large and competing corporation. Why would it not want the same rights to get involved in every US state the way Toyota or Proctor&Gamble does. Today we have a shrinking economic pie so the dollars and resources the FedGov Corporation can acquire means less dollars and resources for the private sector corporations