SCOTUS has demonstrated, as I pointed to in Raich, a willingness to engage in staggering contortions to reach/justify/support a goal. Accepting your reasoning, however correct it may (or may not) be, would mean massive changes in what constitutes contraband and how it may be suppressed - a degree of change SCOTUS is rarely willing to cause (and certainly not over cannabis).

Your reasoning has been tried, and failed. People are working very hard to make such reasoning work, and are making little progress.