Do I understand you correctly as saying that if two businesses in two separate states are conducting trade, that does not fall under the scope of the commerce clause, because the state governments themselves aren't engaging in commerce?
If that's the case, then that would also apply to two businesses located in two separate countries. Yet the founders were clear in their intent that that sort of thing be subject to federal control.
Frankly, MamaTexan's interpretation does seem to be awfully narrow, but to admit much more opens the door to what we have today.
Joseph Story, Commentaries on the Constitution 2:§§ 1073--91
§ 1075 The constitution is one of limited and enumerated powers; and none of them can be rightfully exercised beyond the scope of the objects, specified in those powers. It is not disputed, that, when the power is given, all the appropriate means to carry it into effect are included. Neither is it disputed, that the laying of duties is, or may be an appropriate means of regulating commerce.
But the question is a very different one, whether, under pretence of an exercise of the power to regulate commerce, congress may in fact impose duties for objects wholly distinct from commerce. The question comes to this, whether a power, exclusively for the regulation of commerce, is a power for the regulation of manufactures?
The statement of such a question would seem to involve its own answer. Can a power, granted for one purpose, be transferred to another? If it can, where is the limitation in the constitution? Are not commerce and manufactures as distinct, as commerce and agriculture? If they are, how can a power to regulate one arise from a power to regulate the other?
It is true, that commerce and manufactures are, or may be, intimately connected with each other. A regulation of one may injuriously or beneficially affect the other. But that is not the point in controversy. It is, whether congress has a right to regulate that, which is not committed to it, under a power, which is committed to it, simply because there is, or may be an intimate connexion between the powers. If this were admitted, the enumeration of the powers of congress would be wholly unnecessary and nugatory.
Agriculture, colonies, capital, machinery, the wages of labour, the profits of stock, the rents of land, the punctual performance of contracts, and the diffusion of knowledge would all be within the scope of the power; for all of them bear an intimate relation to commerce. The result would be, that the powers of congress would embrace the widest extent of legislative functions, to the utter demolition of all constitutional boundaries between the state and national governments.
So yes. commerce among the states means just that. To have it otherwise undermines the whole point of FREE enterprise!