This. The ARM ecosystem didn't get a good prebuilt Docker container story until the Pi4, but it was somewhat doable on the Pi3 if you were willing to recompile 80% of containers from scratch. I can only guess that additional adoption fueled the critical mass of incentives for building for ARM as a rule rather than as an exception.

>it was somewhat doable on the Pi3 if you were willing to recompile 80% of containers from scratch.

If Pi3 was so popular, why didn't it exist as a binary?

The pi3 CPU used an older ARM spec, which had issues with producing good binaries for e. g. Go-based builds (I remember that quite vividly).

Beyond that, I can only hypothesize that Docker on non-x86_64 (or multiarch Docker, in general), was very difficult to kick-start for whatever reason. This may have been compounded by the fact that Docker wasn't as broadly adopted by hobbyists back then, so demand for ARM builds want that great.

https://gist.github.com/tyrell/2963c6b121f79096ee0008f5a47cf... looking at this, it seems that debian added it at least 3 years ago and even in 2016 there was a binary, unless you knew about it and it sucked.

But the systems already worked on Arm, that's the point!

Getting more attention to the platform was definitely a good thing, exposing more people to a different architecture, to having a machine cheap enough to just play with, to all sorts of great stuff.

But Linux and BSD themselves were already mature on arm by that point.