> There's just not a global quota,
There is no global quota. There are national quotas set by every country's government. US law nominates the DEA as the agency which does that for the US. Each country's government reports their national quotas to a UN agency (the INCB), but the UN agency has no power over them – at the very worst, they might criticise your quotas, but probably not even that; and more powerful countries (not just the US, even middle powers like Australia) can ignore what UN bureaucrats think with impunity – some poor developing country it may be a different story, especially if aid decisions are tied to getting a "good report card" from those bureaucracies.
And while for the DEA, setting these quotas is part of some grand moral/ideological crusade, for EU governments and Australia it is just technocratic paperwork – so of course those governments approach the issue much more reasonably than the DEA does.
> but DEA rules, which effectively operate extraterritorially, create huge distribution problems.
I don't see how they do. Lisdexamfetamine sold in Australia is manufactured by Takeda in Germany and Ireland. The DEA lacks jurisdiction over what a Japanese company does in EU and Australia. Although the drug was originally developed in the US, the Australian patent is currently owned by the Japanese parent company, not its American subsidiary, while the American subsidiary owns the "Vyvanse" trademark in Australia; anyway, DEA jurisdiction is based on manufacture in the US or US import/export, not country of development or IP ownership.
> If manufacturer A has to shutdown production (which, from the document, seems to have been one of the issues with Takeda), the end result is less production even though other manufacturers could theoretically pick up the slack.
In Australia's case they can't because lisdexamfetamine is still under patent, so other manufacturers are illegal – not because of the DEA, because Takeda will sue them. Takeda could license other manufacturers voluntarily, but why would they do that? That might be great for patients, but probably not so great for their shareholders.
I'm no fan of the DEA, but blaming the DEA for something that happens in Australia appeals to people emotionally even if it isn't true, whereas blaming patent law and the business decisions of a Japanese corporation is more truthful but less emotionally satisfying.