Google's, but especially Sundar Pichai's, stubborness to make Android more PC-like to the detriment of Chrome OS meant that Apple gets to do multi-windows natively before Android - which should've had it at least two or three years ago.
Sure, Android M is likely to get multi-windows as well when they announce the final version (maybe), but we've still moved from Android getting some features two or three years before iOS, to Android and iOS launching very similar features about the same time.
This is a big problem for Google because Apple can release the new OS with the new features to 50% of its users within a week and to 85% of its users within a year. It takes a certain version of Android to do that at least 3 years.
If Google can't release its major Android features years before iOS anymore, then it needs to make upgrading Android devices by itself an even bigger priority, rather than leaving it to others.
Most of Google's stuff seems to come across the year, not waiting for I/O with updates to core apps like Maps, Mail happening almost every Wed. For example apps like Keep, Spotlight Stories, Inbox, etc. A lot of the APIs come packaged as Play Service updates.
I/O literally feels limited to underlying platform performance improvement announcements.
Why do Android users update slowly? I have a few Android devices and I think they pop up with a message from time to time "new os version ready to install". But I am not sure. That shows how much I care :-) But I guess it is that way and then why would anybody not update?
Android users update slowly because Android updates depend on the OEMs, and the OEMs update slowly or not at all.
With iOS, Apple releases an update, and then everyone with an iOS device made in the past N years (where N is 4 or so at the moment) can download it more or less immediately.
With Android, Google releases an update. Then the OEMs slowly start working on updates for their various devices. If they feel like it. Often they just don't bother. Then if you're lucky your OEM finally gets their job done and you can update. And by the time that happens, you're lucky if it's only one or two point releases behind what's now the latest.
And for phones distributed through carriers, once the OEM provides an update, it then (probably) gets tested by the carrier, and only then (eventually) pushed out. Sometimes the carriers don't even distribute updates the OEMs provide.
Most Android users can't update. Their device gets updates for maybe 12-18 months, then nothing. They have to replace the device to update it after that.
Because a lot of phones are locked down by carriers that are slow to issue over-the-air updates. Even non-cellular tablets need manufacturers to issue updates before most users will apply them.
Another big reason is that you don't need to be on the latest core Android version to get a lot of the newer functionality. To get the latest iOS Mail app, you need to update your whole iOS. To get the latest Android Mail app, anyone with a reasonably modern Android version can download the latest app.
Device manufacturer like Samsung release dozens of smartphones per year. The reality is beside their flagship devices the support is sub par, after a single digit months you won't receive any updates. If you use a leased smartphone from TelCos, you will have to wait for OTA updates which can take additional time.
Google migrates this by almost forcing updates over the Google play store framework. And one can decide to buy the device from another Android device manufacturer, ones that are known to support the device for several years.
My Android tablet still doesn't officially have anything beyond Android version 2.3 and I had to root/jailbreak and install Cyanogen to upgrade to the 4.X releases.
I stopped updating my Xoom because I started to notice performance hits from updates. Hardware only lasts so long against modern software that is only or mostly tested on new hardware.
Because Google decided that the Android version must be coupled with the Linux version. And Linux is not able to run old drivers, so vendors must update drivers for old devices to new Linux version.
So either Google should support old Linux kernels with new OS releases or Linux should provide stable kernel API (which is considered nonsense in Linux world) or some kind of compatibility layer.
Sure, Android M is likely to get multi-windows as well when they announce the final version (maybe), but we've still moved from Android getting some features two or three years before iOS, to Android and iOS launching very similar features about the same time.
This is a big problem for Google because Apple can release the new OS with the new features to 50% of its users within a week and to 85% of its users within a year. It takes a certain version of Android to do that at least 3 years.
If Google can't release its major Android features years before iOS anymore, then it needs to make upgrading Android devices by itself an even bigger priority, rather than leaving it to others.