Burn in is a inherent problem of AMOLED. For some it could become quite severe within short period of time; and, for others, they won't notice along the whole lifespan of the device. Please don't assume everyone should use their device as the way you did. Even if someone choose to display static image, such as their kid's photo, constantly, that's their choice. If such style of using will cause hardware problem, then there is a problem, there's no way to say it's not exist or "you wouldn't notice", "you shouldn't care" etc. You won't know others' standard of good and bad and you have no right to judge people's way of using right or wrong.
As an end user, there's no need to help manufactures to window-dressing inherent defects of certain technology. Instead, criticism has long been a strong power to push techs forward. Even if you are not suffering the burn in, you should at least criticize manufactures not educate perspective customers to be aware of this potential problem.