The overlap between these Markdown formats is actually larger than with many other formats. Possibly even larger than HTML’s overlap back when MS Explorer was the dominant browser.

> Possibly even larger than HTML’s overlap back when MS Explorer was the dominant browser.

No way. You were never left in doubt about whether a normal HTML tag would work, or whether tables were available or would become a jumbled illegible mess, or whether a line break in the source would become a space or a hard break. And that’s just the first three things that occur to me.