In order for a rate limit to be effective, at some point it has to apply, and at that point, I'm told "no." More concretely, in order to implement a rate limit, you have to sign an electronic log book, and the government can view that log book whenever it likes, without any sort of review or auditing, of course.
This isn't the primary concern anyways, the point was, in order to implement this seemingly simple action, many liberties have to be sacrificed and the boundary between innocent and criminal and government and private business become significantly marred.
Perhaps those sacrifices are immaterial to most lives and could be ignored without consequence, but the originalist in me says this is folly, and as I've shown it's easy to think of the dangers that some innocent people might endure as a result. Worse, comparing these dangers to the outcomes of the system itself, the whole endeavor seems to have negative value.
Finally, as we've seen in history many times, now that this electronic logbook exists, it's use will naturally continue to expand until the government has secured for itself the right to view nearly every single "questionable" purchase you make at a pharmacy.
It's an entirely unaccountable act from the government. I'm not sure why anyone would expend effort minimizing it.