> Well, if you look at large-scale carefully controlled data, unionized firms tend to be at least 10% less productive than their non-unionized counterparts.[1]
It's not large scale or even necessarily generalisable. I don't think a study limited to 83 "Sawmills in the Western U.S." can be presented as an example of unionisation in general.
> However Amazon is barely profitable as it currently stands
Amazon actively avoids profitability... Modern economies do not reward profitability, they increasingly reward the promise of potential future profitability. Amazon is perfectly capable of earning a healthy profit, but it is actively incentivised not to in favour of chasing further growth. Uber, WeWork, and Doordash all exemplify this attitude; although it could be argued that they are incapable of profitability at all.
Companies are actively choosing to remain in the red in order to stack the house of cards that little bit higher, steal a little bit more of their market before they turn around and exploit the fragile and artificially inflated position they've bought their way into.
> The most defensible thing you can say about this is that the cost is primarily borne by the shareholders rather than the consumers.
Surely the most defensible thing is that the workers are fairly compensated and work in humane conditions? We seem unable to convince Western corporations to not use child or slave labour, but at least we don't attempt to justify it by saying "Iphones would be more expensive without Uighur work camps".