That's the sort of yak-shaving I will never do. I'd rather just not use such a primitive unix and/or be in a job where one of pdksh/ksh/zsh/bash is not available at all.

Well it’s good that you have the choice to; but it’s also not all that difficult to understand that not everyone who needs to use your script, has that choice.

That's cool. We all decide for ourselves what markets we're willing and unwilling to address. But the market that involves "primitive" unix is lucrative and that can be worth it.

For me as a developer, it's not a big deal. You can do all the same things, just in a slightly different way, and you have a script that can run almost everywhere.