Still, as the creator of Markdown we would have much preferred to have him on board in some way. That is why we invited him into the working group 2 years ago, that is why we waited 2 weeks to hear back on the spec we produced before going public, etc.
It does seem like the differences are irreconcilable at this point, not because we changed Markdown – our goal was to build an extremely faithful, compatible version of Markdown that respected its plain ASCII origins from day one – but because Gruber views ambiguities as a feature.
I personally find this irrational, the idea that some poor hapless user on site A would type the exact same Markdown they used on site B and get a different result, is in any possible way a good thing.
But Gruber does. He made that very clear in his latest round of email responses to us.
I think a fine outcome from all of this is if the original creator of Markdown suddenly finds the time, 10 years later, to do a little bit of work maintaining the open source thing they created.