Seems like a lack of creativity, plus painting themselves into a corner by promising unlocked bootloaders.

Samsung owns SmartThings, a smart home platform. They could've come up with a suite of apps for turning your phone into a SmartThings-connected camera, or motion detector, or remote control, or button panel, or a dashboard, etc. Either charge a little for the apps, or trust that sucking people into the SmartThings ecosystem will cause them to buy hubs and other devices.

Users might be more willing to upgrade their phone if they can turn the old one into a baby monitor vs getting scammed on a trade-in or letting it sit in a drawer.