I mean... I guess? But I'm pretty sure the effort and manpower already being expended trounces any argument from that direction pretty easily, and involves notably more risk for employees and agents, as well. You can't tax catch or control the stuff without manpower, but right now they've got no tax or control, and significantly more incentive to avoid being caught, and are still having to expend the manpower. Means pretty much anything coming in on that front is an improvement. That's not even getting into the issues involved with how gov't folks have been trying to bleed some dosh from the mess. Less incentive to abuse civil forfeiture laws and shit would be pretty nice.
If you're running effort calculus there's basically no way for the current state of things to be more efficient or less burdensome than a state of legalization (or at the absolute least decriminalization). Fact that the criminalized aspect of things makes some of organizations like the ATF's other duties something more of an issue is loitering around, too, heh.
Pretty sure there's some similar stuff with microbreweries, at least in some states, so far as the "Up to a point, then we've got problems" thing. Know there is with fishing and hunting, in most(/all?) parts of the country. Seem to do a'ight on that front, least from what I've seen. Enforcement's kinda' loose, much like it is with road law and speeding, but it seems to do decently for keeping most folks mostly on the up and up, such as it is. And most is all you really need, at the end of the day, at the very least with something as relatively harmless as pot.
Also think you're somewhat severely overestimating how much of our population would bother maintaining a garden plot if an alternative of some sort is available, ehehe. That shit takes effort and time, the corner store (or whatev') doesn't.