Small and fragile = lite weight. And all of those spacers and glue is to keep everything in place and prevent those small and fragile parts from breaking as you use the phone. If you want a tiny, lite phone there are compromises. And Apple's mantra has never been serviceability. It's about getting you to upgrade to the new cool thing every 1-2 years, way before the phone would normally need servicing. And the Apple store really only services new batteries and screens. For pretty much everything else they just give you a new phone.