Earlier quoted context omitted.
It feels like the aversion to the "trillion" market value is strictly psychological in response to an arbitrary order of magnitude. Keep in mind that the total value of all US companies combined as of March 2021 is $49 trillion ( https://siblisresearch.com/data/us-stock-market-value/); Amazon represents just 4% of that. If we were to try to define Amazon's market, there's no reasonable definition you could come up wi…
The linked article allows that Amazon has much more than a 40% share of certain "segments": > Amazon has well over half of US book sales, and probably three quarters of ebook sales. So if we’re arguing about how Amazon runs its books business, it unquestionably has market dominance. You have to pull out a segment, not the whole company. To speak more generally, my understanding is that arguments that Amazon is a mono…
Notwithstanding that, I think the general point is that this is a vertical acquisition completely unrelated to that market, in which Amazon has nowhere close to that kind of market share.
Keep in mind that nobody here is arguing that we ought to have a free-for-all in acquisitions and do away with the FTC entirely. It's just that the FTC doesn't operate off of knee-jerk reactions to absolute dollar amount market valuations. Instead, the level of analysis is one that's more in line with what the GP commenter has been arguing.