The recycling is gonna happen anyway, so the only real issue is the costs. If I recall correctly, glass and aluminum is virtually infinitely recyclable, but plastic can degrade through the recycling process, but takes much longer to naturally degrade than aluminum.
Don't forget Apple has discontinued the plastic MacBoks and now only sells the aluminum unibody Pros and Airs.
Cost is a pretty big deciding factor for a user when they break a device and have to decide whether to fix it or trash it.
This is where history kicks in; The iPhone 4 is probably the longest lasting and most repaired smartphone out there thanks to that durable stainless steel chassis, only beating the iPhone 4S because it is older. People are happy to replace the screen on a 4/4S several times, because it's affordable and worth it. The chassis protects the internal components and stands against wear and tear very well. Its durability allows it to never need replacement, unlike even the iPhone 5's housing, which can dent enough such that it doesn't fit a new screen.
Because Android phones typically have higher resolution screens (and quoted specs that easily marks how outdated a particular model is), they also cost more, and that gives less incentive for a user to want to repair it when they could upgrade to a phone with a newer design, more RAM, better chipset, higher resolution/display density etc.
The thing is, Apple is pretty much the trend-setter for these things, so expect to see less removable batteries and more aluminum, in both laptops and phones.
