Perhaps I can build on Maude's comments.
First of all, I don't know that one of the goals was to prevent the proliferation of corporations so much as it was to ensure that when corporations are used, the appropriate tax results occur. You mentioned as well the use of an asset that in one corporation would be actively used in the business, transferred to another corporation, and then used by corporations within a related group in their businesses. One of the key exclusions for this small business deduction or eligibility reduction is that income from active assets are excluded from that, which could include an asset that is used by a related company in its business.
As Maude said, these are supplementary to the existing small business deduction grind that occurs in respect of taxable capital employed in Canada. Those do apply in respect of an associated group of corporations. Just incorporating more companies won't get you out of the rules. I can't say there's no planning out there to try to avoid the rules. There certainly is an incentive to do so. But in general terms, it applies based on a group concept.