Yep, the prerequisite for AirDrop, Handoff, SMS/voice call relay to your iPhone, etc. was a Bluetooth 4.0-capable wireless chipset. You could actually purchase

Yep, the prerequisite for AirDrop, Handoff, SMS/voice call relay to your iPhone, etc. was a Bluetooth 4.0-capable wireless chipset. You could actually purchase an upgraded wireless module from 3rd-party sellers on Aliexpress/Amazon/eBay for <$100 and install it in an older MacBook with a Philips screwdriver. Apple made no money in that transaction, and you got to have one of the “killer features” of the latest Macs for a great price. A better argument for planned obsolescence might be that Apple discontinued this modular design in the current MacBooks and integrated the wireless chipset onto the main logic board, making such an upgrade impossible in future if a new feature has a dependency on more recent wireless hardware.