The issue is that not everything has to be flipped. Numbers are an example but think about LTR words embedded in a RTL language (some may be urls or email addre

The issue is that not everything has to be flipped. Numbers are an example but think about LTR words embedded in a RTL language (some may be urls or email addresses or untranslatable texts). Designing an HTML page with RTL content is basically a nightmare because the tags are still in English. Actually some programmers do exactly as you say and flip the view completely, including tags, when they work in a mixed document. I have seen this flow with programmers who use vim in the terminal. But not, the cost is really not enormous nowadays. It's really a matter of really easy fixes and some testing. Similarly to many other accessibility features the issue is most often ignored completely, however.