Also, the blog post buries the lede somewhat. I found that this was the most important bit:
Update: Turns out the “unexpectedly positive” was a reaction to day 3,
which covered pre-IUT material. Today, when things turned to the IUT stuff,
it did not go well at all. See the link in the comments from lieven le bruyn
to a report from Felipe Voloch. Unfortunately it now looks quite possible
that the end result of this workshop will be a consensus that the IUT part
of this story is just hopelessly impenetrable.
So while there was an early sense of optimism that the gathered mathematicians would be able to find some way through the papers at the beginning of the week, it seems that optimism has soured as the week progressed.
Science is about publishing results that others can reproduce and check. Failing to make a theory accessible to the world experts (!) in the field is about as useful as not having the theory at all. Despite what some introvert mathematicians may think, science necessarily involves other humans.
If I were one of the experts I would give it that one week and if nothing interesting comes up stop wasting my time on it.
But Mochizuki was answering questions. And its not like there is absolutely no progress. Quoting from the day 5 summary:
> I felt that Dupuy was the one that made the most progress learning the stuff. He told me afterwards that he indeed made progress but is nowhere done yet. He also told me he would take Mochizuki up on his offer and continue to work on understanding the work.
