Working too Hard isn’t gone. I still have it as pdf and Word file if anybody wants to improve this work. Although, I’m pretty sure it was in the Tower gdrive. If it isn’t there, let me know.
And yes, Siltskimmer is gone. It was a bit emotional to see it go, but I haven’t had the time to do anything with it in the last decade… Sadly.
Most of the people don’t have access to the PT group drive, as they are not members of the group. Could you upload to the public share?
I think the issue can be summarised as this:
Far too many people are currently unable to recognise that writing fiction that includes a “problematic” issue is not the same as advocating in support of it.
Until this situation changes, we’re not going to get anywhere with an official WOTC 5e license for Dark Sun.
I had a talk with the other Senators. Officially Athas.org cannot endorse the Working Too Hard supplement for obvious reasons. However, people having it, using it or distributing it is not in any way up to us. 
If @grummore can share it directly, go for it! It just cannot officially come from any of the ranking Athas.org people, or be hosted on any of our spaces. (Sorry.)
Well, yes…
I will say that Working Too Hard is a very good Dark Sun work.
I like Dark Sun and I’ll play it in whatever gaming-system I like. Be it, 2e, 5e or 7e, or even non-D&D like Cyberpunk 2020 or Green Ronin’s ASoIaF game (which, given the way magic works, would do well as a Dark Sun game).
Would anyone like to host it somewhere? I can share it as well.
I think we should upload it to the internet, then take a snapshot with archive.org and archive.is. That would ensure that it would always be on the internet. I can do it if you can send it to me. Once that is done, other people can add it to their hosting sites as necessary.
I found working too hard on my cloud drive. Send me a message if you want it. Later I will find a place for it online.