Docker instead has to re-build all subsequent layers when the input of even just one layer changes.

The two tools sit on a different point in the spectrum of simplicity of use though. Maintain build files for bazel (and dealing with other constraints of hermetic execution) is hard time-consuming and it's hard to convince many teams it's worth the effort.

Docker apparently struck a sweet spot in that it's easy to explain how to craft linear build steps and it does a half-decent job in actually caching stuff. Sometimes it doesn't work well depending on your workflow but people then have the incentive to read about how to improve the "cacheability" of their dockerfiles (multistage, reorder, dockerignore, ...). As many things in our craft, the human aspect trumps over technical brilliance.