In reality the "knock on effect" doesn't work, or, more precisely, it only works for the few lucky indies who get noticed and "featured" by the store and the big companies who throw lots of marketing money and who can use their connections Most indie devs I know, who don't have journalistic acquaintances sell very few games on IOS and android store (much worse on android) and not with crap games, there are many polished and fun games that just don't sell They're lost in a sea of similar apps As for Windows 8, I don't think Microsoft will restrict it to its own appstore, they've been sued so many times for anti-competitive behaviours, they'll probably leave he door open.
Angry Birds has a much bigger audience but the actual numbers aren't that different I'd say - of course this may change over the next few years because of whatever they make using the popularity of the birds. After a quick search Rovio's revenues were about $10 million in 2010 and about $106 million in 2011. Mincraft has sold about 6 million units on PC, I don't have exact numbers but roughly 4 million at 15€ and 2 million and 20€ - that's 100 million in € - pretty much on par with Angry birds but just on PC - it's not counting Xbox, Android, iOS, it's not counting that these revenues don't include any free giveaway adbased revenues, not plush toys and other merchandise stuff (which seems to be responsible for 30% of Rovios revenue). So - even though it's true that Angry Birds is likely to be the much bigger brand in the long term I absolutely don't see it on the winning side right at this moment.