Androids pixels are display pixels, there's no post-render scaling. So no pixel cracks, no blurriness, etc... Density is instead handled mostly at layout, as it should be.

You can't just make the windows bigger on a high res display, the text will be unreadably small.

Of course you can. Text only ends up unreadably small if your text is specified in pixels. Which on a density-aware toolkit (like Android's) it isn't. https://developer.android.com/training/multiscreen/screenden...

This is also best practice on many other platforms, too (eg, 'pt' and 'em' units). This is far less commonly followed on most toolkits, though, but it's the norm on Android.

And now your controls are either blurry or don't match the text size or you redid them all in vector art.

Text size controls are in iOS as an accessibility feature (dynamic type) but it's not always on and it can't be the approach to HiDPI.