The purpose of these reports is to help Authors figure out how to run their careers, not to support anybody's perceptions of how important a given ebookstore or format might be.
As to the whole, "there is more than the US out there" attitude, well, there is this:
http://www.economist.com/news/essays...ountered-vault
and this:
http://www.thebookseller.com/futureb...ok-market-2014
The US alone is well over half the world ebook market.
Add in the UK (where Amazon is even more dominant) and the ratio skews even further against epub, which seems to be what offends so many.
(Oh, and in the third biggest market, Japan, Amazon is also over half the market.)
Like it or not, Authors are going to take their stories where the money is.
Like this:
http://kriswrites.com/2015/10/07/bus...thor-earnings/
This is where the business is headed.
Handwaving it isn't going to stop it.
Competing ebookstores stepping up is the only solution and, so far, they aren't.