It's a MacBook appliance designed to die
What Apple have done is create a laptop as an appliance like an iPad only much worse. It's got designed obsolescence built in.
If you check out ifixit.com's teardown at https://www.ifixit.com/Teardown/Retina+Macbook+2015+Teardown/39841 you'll discover that this thing has been carefully engineered to be practically impossible to upgrade or repair in any significant way.
*Proprietary screws to hold some components together.
*The batteries are glued down into the case - so when the batteries die, end of laptop. Buy another
*The Retina display is a fused unit - no way to change anything in it.
*The processor, RAM and flash memory have been SOLDERED to the motherboard - problems with any of those things and you're screwed.
*The motherboard is glued to the case.
*Everything connects through one USB-c connector, power and peripherals, the lot - when that wears out you buy another laptop.
This thing is designed to have a limited lifespan. It's the ultimate throw-away laptop appliance for rich people, because the first component to fail causes the laptop to be useless. It's designed for landfill only.
ifixit.com gave it 1/10 (its lowest score) for maintainability.
If Apple had put a clock showing how long you've got left before it's garbage, it could not have done more to be an expensive throw-away.
Biting the hand that feeds IT
