As an Australian I can confirm that Amazon launching here was a hotly anticipated disappointment. Amazon US is (was) far more popular in Australia than Amazon AU is now, for many reasons including price and breadth of product.
In order to force use of the AU site they blocked sales from the US site to Australian customers, which caused endless irritation and frustration.
Their excuse for the block was the new GST laws but they have removed that now so the US site can be used.
It seems that the relatively quiet launch and slow growth has been intentional. As long as Amazon maintains a decent level of investment here I think they will continue to grow and possibly eventually be dominant.
Only recently have they ramped up advertising and started putting their listings onto Google Shopping.
SEA seems like a terrible place to run an e-commerce marketplace. A bunch of competition that seems pretty content to run at a loss to try and build market share.
Here you go with the source: https://www.shopify.com/enterprise/global-ecommerce-marketpl...
And Amazon is also big in Brazil, Mexico, Japan etc. I think it is suffice to say that my point wrt Amazon dominating global eComm is fairly well laid out. Well, except for "China".
I'm very, very surprised not to see Alibaba/Express/Bao being present in Brazil in their data. And same for the Middle East.
Given that, I greatly doubt the veracity of their research.
The expected investment also doesn't match Alibaba's, the Chinese have apparently come up with $1.1 billion while Amazon is coming with only half of that value, i.e. $600 million. But maybe they're doing better in Thailand or Vietnam.
[1] https://www.entrepreneur.com/article/320410