@federico3 As someone with a hat in this, it's because other formats are pretty arbitrary too. #Markdown was designed to still be readable as plaintext -- something it fails at, yes, with that awful link syntax -- but the same complaint can be levied against ReST, #AsciiDoc etc which all have arbitrary and unusual syntax patterns that work for a parser but don't necessarily work for plaintext.

And plaintext, unlike programming languages, depends more on aesthetic principles that are more personal. Programmer may argue about line-break before `{` but the code still compiles -- that's not the case with markup languages!

For my databaseless forum I invented a markup syntax where the output can be copied and pasted as valid input: just leave the `*` & `_`'s in and style with CSS, it works surprisingly well. For ReMarkable I hewed closer to plain-text aesthetics but it needs some revisions, and it's difficult to swap one bad syntax for a better one down the line when the format is already in wide use.

Markdown would have seen a decline, until GitHub took off. I think that really cemented its modern usage more than anything. You can stab it with your steely knives, but you just can't kill the beast 🤷