why is the global south locked into producing low-value commodities for export while the west holds monopoly power over advanced tech, pharma, aviation, producer goods?

They're not. They're locked in there by shitty values and rapacious states and insecure property rights.

Also: oh no, not the horrid hellhole that is AUSTRALIA.

Also #2: stop talking about "extracting" and "surplus." and "periphery." Those are not real things