Who cares if they won't share the driver source you'll have to throw it out after 2 years anyway.
By the way I think Qualcomm do share sources (through code Aurora?). But they don't upstream them.
Writing this from a zl1 running LOS17.1 using Snapdragon 821.
P.S. Big thanks to mosimach for being device and specialised kernel fork maintainer.
The early to mid 2010 android devices are piling up left and right, but the software is old. As phones they're still good enough but network operators build back tower hardware for 3G, so there's another EoL date coming at least for their data channels.
If the drivers are open source you can at least run something like LineageOS or another Android derived open source ROM and still run an updated OS on your old hardware.