I'm wondering...
If Apple chooses to go all USB-C though that means they lose all that revenue and profit from selling chargers. Given that almost everybody goes through several chargers during their MacBook's lifetime that is not an inconsiderable amount. Nobody in their right mind would pay for Apple chargers when they can buy reliable and cheaper ones elsewhere, Apple does not have control of the USB-C patent unlike MagSafe. In this situation it wouldn't surprise me if they bake in extra features when using an Apple charger instead of third party, much like the iPhone 6s battery case.
Or... Maybe they do want to drop them because they are sick of all the complaints, the reviews on chargers on their own site are pretty abysmal. I noticed they dropped the AA charger the second the new keyboard and trackpad was released and that had awful reviews too.