[ilyt]

It's not really problem with being "perfectly specced" or not, it's just matter of inertia.

If markdown just used bold _italics_ at the start, or needed a tag for HTML instead of passing it as is... it would be entirely fine and just as popular now. Or any other generally agreed upon as "good" fix.

But inertia makes things like that near-impossible to change now. Only additions can sorta work and even those are hard as critical mass of dialects needs to apply them for it to work.