The commonly understood meaning of "regulate" at the time the Constitution was written was "to keep in good working order", as in "to regulate a clock".
You can find lengthy discussions and articles about this on many RKBA sites in reference to the meaning of "a well regulated militia".
I think that if the courts were to take it upon themselves to hold that "the commonly understood meaning of 'regulate' at the time of the Constitution was written was 'to keep in good working order,'" nothing would change. I can't think of a single example in which the Congress passed a law under the commerce clause and didn't say that it was doing so in order to promote the interests of interstate commerce. How can a court legitimately question such Congressional determinations? Should courts hold their own hearings on whether, for example, child labor laws are on the whole good or bad for the long run interests of interstate commerce? Should they convene juries to help them decide these issues? Where does the Constitution say anything about courts performing that function? Shouldn't the fact that the Constitution doesn't expressly grant the judiciary any power to regulate the Congress be given some consideration by a court that wishes to become more activist in this area?
People who blame the courts for what they see as an unconstitutionally large federal government are totally missing the boat. If we want a smaller federal government, the only way to get that is to elect representatives to Congress who share our view. The courts can't legitimately perform that task for us.