I recently decided to port some apps to Android and Windows 8 to lower my Apple only risk. Diversification is good right? It's been a really mixed bag so far. 1 of my apps is doing better than it's iPhone counterpart, the rest might as well not exist. 
So far I've done native rewrites. Initially everything was designed specifically for iOS, so when porting I've just gone with native. I may consider some kind of cross platform option for the next completely new app. I haven't decided yet. (In general I think native is better, but there are obviously benefits to writing one version.)
Most developers go where users go, most of the time, until some of them have a reason not to. Luckily for those who don't always follow the money, demand sometimes follows supply instead of the other way around.
Either your parent edited after your post or you conveniently skipped the '(and pay)' in your argument. I'd like to see some solid comparison of revenue numbers between Play store and Appstore. I'm pretty sure iOS would still come out ahead in that regard, until I get disproven on this. Of course I'm not saying that one should ignore Android, since this will quite possibly change in the (near) future, but still, from an economic standpoint it IMO still makes sense to target iOS first.
When something is conveniently enclosed in parenthesis, it means it is an extension or addition, right?
Anyway, yes I replied to the "where users go", and not to the "where users pay" thing, because I think it is two problems.
So apparently, by the numbers, users go Android, but iOS users are currently more willing to purchase apps, right? Maybe. But not sure. I don't think Android users would be that reluctant to pay a small amount of dollars for an app they really want, if it were convenient.
I paid happily for Minecraft, Machinarium, GTA and 4/5 utilities. The problem is probably that the main source of data, the Google play market, is currently not open to transactions in China and maybe other big countries. So, for me, to buy an app I need: a rooted device, the "fake US location" app (market enabler), a working VPN installed on the phone, and a credit card.
I would like to know the numbers for local Chinese markets, but given that they try very hard to attract user it should probably be juicy, or at least very promising.
Do you have experience distributing apps? While the pure numbers are massively Android, my personal experience is iOS will get you far more downloads, so either Android people are not downloading apps, the Android numbers are inflated by devices that use Android but don't lend themselves to apps, or it's just really hard to get an app noticed on the Play store.
How is this at all relevant? Publishing in one app store does not prevent you from publishing in the opposing one.
Services like 500px no doubt have both Android and iOS apps, and they will continue to do so as long as their customers (and potential customers) carry these devices in their pockets.
So long as hundreds of millions of people carry iOS devices, people will publish apps in the App Store in droves, regardless of how draconian Apple's rules are. This is entirely independent of how many other people use Android.
Previous poster is entirely correct, the power to enact change here is entirely at the hands of customers who buy Apple products. Developers have no leverage here, because everyone knows that so long as Apple keeps shipping tens of millions of tablets and phones every quarter, to wealthy people with high disposable income, devs will stay.
2. "Nice, more people will go away from Apple store"
3. "Developpers go where user go (and pay)" (ie iOS)
4. me: "user go Android".
5. you: "How is this at all relevant? do both"
Well, sure you can do both, but I was replying to the "user go Apple" claim above, so it is relevant, or?
There is a reality mismatch with Apple: they do nice tools, but the fact we hear about them a lot and almost all movies, screenshot, etc. seem to show only Apple products, do not mean that most users actually use Apple systems or products (except if "most users" means "most startup entrepreneurs and wealthy folks in SV")
The reality is, to be clear, that all but a tiny not representative fraction of laptops and desktops are running a version of Windows, and almost all but a small fraction of smartphones run a variant of Android.
I avoid Windows and I am not particularly found of Android, but I think not going Android is suicidal for devs, except if they do special elite or niche apps. I did not invent this myself, Fred Wilson said the same many time.
My understanding of the current state of affairs is that 'users who pay for apps' are still disproportionately represented on iOS. That is, there may be more users on Android, there are more potential customers on iOS.
I could be wrong, though - maybe that balance has started to shift?