At least Xiaomi is telling their customers upfront that the reason they can sell their mid and low end android phones on the cheap ( by famously announcing to cap their hardware profit margin at 5% ) is due to advertising. IIRC their high end models do not have ads. Other manufacturers mocked xiaomi for this move, just like they mocked apple for removing headphone jack, then quietly follow the move anyway without telling their customers, which I think is an even bigger dick move.