The problem is that JS perf is so much worse on Android, and adding insult to injury, the single threaded perf of the very fastest Android devices are less than

The problem is that JS perf is so much worse on Android, and adding insult to injury, the single threaded perf of the very fastest Android devices are less than half an iPhone 7. Worse still, Apple devices get upgraded aggressively, whereas Android devices don't, so the long tail of very old very slow devices (mobile devices age in dog years) is enormous. Sad but true.