So Apple's motivations were solely altruistic, whereas mean old Google is just a money grubbing copycat?

I'm being snarky, but it seems a little naive to think either of these companies wasn't eager to capitalize on the lucrative mobile software market. Aren't you also prevented from buying subscriptions or making other in-app purchases within iOS apps (but not through the app store's integrated system)? Seems like that has little to do with malware as it's not just a ban on malicious IAP, but rather any type of IAP that doesn't include the "app store tax" as you put it.

I think both the Google and Apple stores purport to be a generally safe repository of mobile software in order to encourage the sale and distribution of apps, strengthen the appeal of their respective platforms, and generate revenue by providing these markets (for a cut).

When Apple did it, it wasn't at all clear that there would be a lucrative mobile software market. What was clear is that the success of their platform absolutely depended on applications not giving the platform a bad name. And insisting on control was typical Steve Jobs.

Apple's motivations for continuing to charge outrageous fees are, of course, that they want to keep the free money rolling in. And they must have hoped to generate a revenue stream. But establishing tight control had lots of other motivations.

By contrast Google was deliberately creating an open platform on open sourced software. Their decision to lock down this piece was opposite the rest of the product direction. And it is hard to believe that they weren't looking at the demonstration of what happened with the iPhone and were trying to replicate the revenue model.

> * What was clear is that the success of their platform absolutely depended on applications not giving the platform a bad name.*

Yes, but I see this as Apple desiring tight control, first and foremost (as you hint at). Helping cut a potential malware problem off at the pass was a nice side benefit. I see the flow of causation in the other direction here. Apple just wanted control, because that's just how they do things. Initially they weren't even going to allow third-party apps.

This cuts both ways: while you can't distribute obvious malware on Apple's App Store, you also can't distribute perfectly benign things that people want, but Apple has decided is distasteful... to them.

> By contrast Google was deliberately creating an open platform on open sourced software.

I think that's a fairly naive view of it. They believed that open-sourcing the OS was the best way to gain market share (which worked, for all Android's fragmentation and faults). I sincerely doubt it had much to do with some desire for openness; that would contrast pretty sharply with most of the rest of Google.

> Their decision to lock down this piece was opposite the rest of the product direction.

Except they didn't lock it down! I have several apps on my phone installed via F-Droid. The Facebook Lite app used to (I uninstalled FB a couple years ago, so not sure if it's still the case) have the ability to manage and install its own updates (I assume for lower-spec/non-Google-Apps phones in developing markets). If I feel I can trust an app I download off the internet, I can install it. I have a couple of my own apps installed on the phone, without needing to pay Apple a $99 gate-keeping fee, and the software to install them is open source, not wrapped up in proprietary Xcode.

I will be the first to agree that most people don't avail themselves of this option, and an app developer who doesn't publish in the Google Play Store is kneecapping their market reach. But the fact that it's possible (and not even difficult) to do is the point. Sideloading on an iPhone is something that costs money; requires specialized skills, tools, and a particular brand of hardware; and is out of reach for the vast majority of people who (for example) would otherwise sideload on Android.

> * And it is hard to believe that they weren't looking at the demonstration of what happened with the iPhone and were trying to replicate the revenue model.*

I'm sure that was part of it, but... so what? I don't really see this as indicative of a particular mindset.

Apple originally didn’t want custom apps or an app store at all... folks started jail breaking their phones to have insane and cutting edge features from the future like copy and paste.