As I said, the ones listed in the article are relatively recent, all released within the past year apart from the G4, Nexus 6 and a couple of others. There are other handsets that are not listed, and as such those handsets will need to be updated by their manufacturers. There is not really any business reason for them to update these devices, because as you say many of them are likely still running on older Android versions, although integration of the Qualcomm firmware is not dependent on Android version.