> Also note that it isn't just Bash that we'd need to download, but coreutils and other utilities that Bash is really built on top of. We tried to fix a pretty simple bug last year in the Bash installer, and it took two weeks to validate a relatively straightforward, one line change was valid on all the platforms we target.

This clarifies a lot of what confused me in TFA. I maintained millions of lines of bash code, some of which is decades old and run into only a single bash incompatibility that wasn't fixable with shopt. On the other hand, incompatibilities in programs bash is running are rampant, particularly between GNU and non-GNU systems (and even within GNU there are more surprises than you might think). The phrase "different bash implementations" was a major red herring for figuring out what you were talking about.