Even if you ignore all of the issues with Gruber's math (non-Honeycomb tablets matter a great deal, for instance, especially when you're trying to understand the impact of the Kindle Fire), as of July is a very, very out-of-date number. As of the beginning if November, ASUS alone has sold 1.2 million Transformers [1]. A better number is 6 million Android tablets (from Andy Rubin at AsiaD) [2], though that still leaves out important slices of the Android tablet market like the B&N Nooks.
Putting this together, if Amazon hits their (rumored) goal of selling over 5 million Kindle Fires, they'll certainly get a substantial slice of the Android tablet market and quite possibly a majority among US users (depending on what you count, like Nooks). Nevertheless, there will still be a larger slice of Android tablets with Google services and the Android Market, and the Android Market will be dominant outside the US (e.g. if you believe the NPD numbers ASUS might well have sold over 90% of their tablets outside the US [3]).
I'm not able to tell if the [1] link there is "shipped" or actually "sold to consumers" — they seem to talk about selling 1.2M but shipping the 1.8M by the end of the year. Since I doubt all of those are being sold right away, I'm not sure how that adds up. Same for [2] — does Rubin's "out there" mean shipped or sold to customers?
I thought ASUS was being clear in [1]. They've sold 1.2 million so far and plan to ship at least another 600k by the end of the year. At this point, they can't count those 600k as sold since that would be predicting the future.
As for [2], I'd expect Andy Rubin's number is based on the number of tablets accessing Google services [4] (which isn't surprising since that is the number Google can most easily observe). Given that, it seems clear to me those 6 million count as sold.
Thanks. I found estimates of 3.4MM android tablets as of mid October [1]. Pretty dismal figures or Google would be trumpeting them. Still, I think most of my point holds -- if Amazon sells 5MM kindles they won't just have a good slice, they'll have over half the market. And if your outside the US figures are correct, Amazon will hold an even bigger slice of people who can afford and will purchase android tablet apps.
Also, don't be so quick to conclude Amazon will have over half even the US market. You're forgetting to count the Nooks (which have to be counted if you're counting Kindle Fires, of course). The best number I've found is about 3 million from March 2011 [1], with B&N claiming an unspecified "millions" at the Nook Tablet launch.
That means, to win in the US at the end of the year (since they're not competing internationally), Amazon has to beat:
* ~3 million Nook colors sold as of March 2011 +
* Nook Colors sold between March 2011 and the end of the year +
* ~1 million Android tablets sold through October 2011
(NPD numbers excluding TouchPad) +
* Android tablets sold in November and December
Theoretically, 5 million might be enough for Amazon, but you'd have to think:
* that Nook Color sales collapsed soon after March
* the Nook Tablet will flop
* Android tablet vendors can't even replicate their sales-to-date during the holiday season (even though there are new quad-core models and cheaper 7-inch models, among other things)
Personally, I think the more interesting race is Kindle vs Nook one-on-one. Nook, of course, has the early lead, but Kindle is selling faster. I think everyone expects Kindle to win eventually (absent a game-changing move by B&N), but will it be this year?
You seem to be presuming that people outside the US can't afford or won't purchase Android apps.
Given that outside the US includes Europe, Australia/New Zealand and the more affluent parts of Asia (Japan, Korea, Hong Kong, Singapore, Taiwan, etc.) and those are the places I'd expect official Android tablets to be selling, that assumption seems strange to me.
Putting this together, if Amazon hits their (rumored) goal of selling over 5 million Kindle Fires, they'll certainly get a substantial slice of the Android tablet market and quite possibly a majority among US users (depending on what you count, like Nooks). Nevertheless, there will still be a larger slice of Android tablets with Google services and the Android Market, and the Android Market will be dominant outside the US (e.g. if you believe the NPD numbers ASUS might well have sold over 90% of their tablets outside the US [3]).
[1] http://www.maximumpc.com/article/news/asus_eyes_18_million_t...
[2] http://www.theverge.com/2011/10/19/2500959/6-million-android...
[3] http://www.electronista.com/articles/11/11/22/npd.shows.hp.l...