Why a zoo of distributions with different features?

[mfritsche]

<snarky>Because we like animals?</snarky>

You are right, we are getting close to mainline kernel support, 5.4. But, in the mean time we are using an older kernel, 4.4.x, probably the latest when Rockchip wrote or updated thier driver's for the RK3399. It has to be installed in to the distro, and we have several people willing to do that intigration work.

Additionally, it's a bit of alchemy to find out which driver version (the hacked ones from RockChip, Broadcom or whoever, or the open source version in the mainline kernel) work with what version of the (often closed source blobs) of the firmware(s).

And that, kids, is the reason why general purpose ARM device just don't get off the ground: licencees of ARM cores make their chip, hack a specific x.y.z-whatever ancient linux kernel version and sell it as an "appliance". Source sometimes gets released if someone asks, but almost never updated to newer kernel versions, or even with a non-heavily-patched-hacked-and-broken version x.y.z  

It's the same for android smartphones, "NAS"-Appliances, and for all "RPI"-Replacement boards.