I think it's interesting for figuring out whether this was a profitable long-term move for Amazon requires thinking about revenue rather than profit. Compared to the temporary loss due to the fine (who knows what will actually end up getting paid, how it gets paid, etc) the revenue share (that will recur) that matters more long term.

If you paid 1.3B one-time to secure yourself a revenue stream that pays out 200MM than you would have otherwise gained a quarter, you're going to make your money back in ~6 quarters. It's absolutely worth it to take the temporary hit to income (obviously better if you didn't, which they were counting on) -- in fact knowing up front it'd be worth it.

Considering only the hit to short term income makes sense only in the short term, I think -- the Italian industry that was muscled out because they didn't want to use FBA, or the italian logistics providers that weren't chosen because of the incentive to use FBA face more difficulty. Amazon is amplifying solidifying it's own revenue streams, and that effect is likely to persist past a quarter or two.

I may be mistaken but I think of it like the other non-profit making tech companies that are floating around -- unexpected losses in the service of market domination are worth the gained and/or even-more-stabilized revenue streams.