Having worked in a university mathematics department I noticed that the pure mathematicians tended to keep themselves to themselves, for instance not attending talks by visiting mathematicians unless it was of direct relevance to their research. In contrast, we theoretical physicists would listen to any visiting speaker just for fun - even on occasion experimental particle physicists, applied mathematicians or computing specialists. Perhaps pure maths is just more deeply specialised and leaves no possibility of such dilettanteism.

I think it's probably because it's very difficult to understand a pure math talk if you didn't already have significant understanding of the subject before the talk.

I don't work on pure mathematics, but I work in a field of computer science where there is both theoretical and empirical/applied research, and I do, and enjoy doing, both.

However, when it comes to attending talks, I do go to a lot of talks on empirical subjects just for fun, but I hardly ever go to a highly theoretical talk for fun. I only do that if the talk is highly related to the specific work I do; if you see me in a theoretical talk otherwise, it's probably just for social compromise.

The reason is that I can perfectly understand the gist of an empirical paper in 20 or 30 minutes, where there is no way I will understand a piece of theoretical research by listening to a talk if I haven't gone through the paper carefully before (and if you have done that, there is often no point in going to the talk anyway). Honestly I think the talk format doesn't lend itself too well to highly theoretical work. I have learned a lot about empirical research and obtained many useful ideas from talks, but in the theoretical field, the useful ideas and insights I got from talks are few and far between, and I would probably have obtained them more efficiently from reading papers anyway...

There is literally only a handful of mathematicians that are qualified and they have gone to Oxford to sort it out - bar mochizuki.

Yes, part of what I was trying to say is why not get that handful of folks together and go to Japan, to the source. Logistics? Ego? Funding? Perhaps a trip is in the cards...

This was just one workshop that happened to be at Oxford. Probably it occurred the other way around to you imagine - "let's host a workshop here [at Oxford], what shall be the topic?"

Article says there is another one planned in Japan that will no doubt be attended by a (proper, less those put off!) subset of those at Oxford.

Money and time. I'm sure you could straight-up pay some of the qualified mathematicians to figure it out, but you'd need to make it worth their while. Offer to buy out their salary for a couple of years, plus hire them a few postdocs and grad students to further their own projects, and I'm sure a few would be happy to help. But it would cost the better part of $1M for each guy.

There was an earlier workshop in Japan. From wiki:

"A workshop on IUT was held at RIMS [Japan] in March 2015 and in Beijing in July 2015. A CMI workshop on IUT theory of Mochizuki was held in December 2015 in Oxford, IUT-Oxford (2015). A workshop on IUT will be held in July 2016 at RIMS."