The real reason is the shitty CPU on typical low-end to mid-end Androids. They suck at running JS. And I mean REALLY suck, as in 5-10 times slower than an iPhone.

I recently came across a ridiculous example of a high-end Chinese phone (700$) where one our web app's interactions that normally is near-instant, took 6s instead. Turns out that besides the generic issue of poor JS performance on Android (due to CPU), this particular manufacturer decided to deliver on their ridiculous battery life claims by...running all JS on a low energy CPU core.