Go read the article on the front page of DPreview discusses how more megapixels has nothing to do with quality. I shoot pro Canon cameras
and It would be safe to say the EOS 1D a $12000 dollar camera who's sensor
is 18mp blows away any camera phone sensor and most would agree any conventional digital camera as well. So according to your implied logic the
Nokia 1020 phone( 45 Mp) has a better sensor than the Canon pro camera.
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=855962&is=REG&Q=&A=details
The reason Apple doesn't go around touting how much faster their A7 processor is compared to Samsung or any other phone, or the study that just showed
the touch screen response is 2x faster than any android tablet or phone, or how many megapixelsis, because they are focused on the end users overall experience. In other words look how amazing this picture is taken with the iPhone 5s. If you really want to know how far ahead Apple is go to the andantech site and read the review of the camera and a7 processor on the new iPhone 5s. So if Apple stays at 8Mp I will know the reason is because there were other much more significant changes to the camera such as increasing sensor size, improved algorithms etc, all thing that can drastically improve picture quality.
In fact in order to school you look at the Moto x. The image quality has been horrible. Just today they released a software update that results in the phone having one of the highest quality cameras of any cell phone. All that was changed was code. Just shows how important the software side of the camera is in contribution to camera quality in the digital world.
http://www.anandtech.com/show/7353/moto-x-update-dramatically-improves-camera-quality