I just found out about this project from this post, and I've spent my whole night reading up on it and the ecosystem and its past. I LOVE the vision and was so excited to read about it, but then sad to realize I'm joining the party too late. It's been a roller coaster of a night.
I think the most important piece of tech that Sandstorm was working on was the capability based security and the powerbox concepts (which I recognized as being similar to Android's capability apis but for the web). I don't see the decentralized data or local servers being an easy sell any time soon, but I can see the capabilities security working really well within the browser, and more importantly with existing SaaS ecosystems.
If we could get a new browser API for websites to offer to register available APIs for jsonschema based type defs through a manifest file, then users could allow those APIs to be included in their local browser registry. Other pages could request (or offer) data from those APIs, and with the user's permission, the browser could do the necessary oauth handshake and use the API, passing data to/from another service in a secure way behind the scenes.
As well since it would be a browser API, a webpage looking to call an API would be able to request provider info and show the appropriate in-app UI for selecting a service, which sounds like one of the problems Sandstorm had.
No one would have to worry about whether they implement a dropbox api or onedrive api, the page would just have to show the 'file service' selector and call the user selected api with a file. So I'd expect every SaaS out there would jump at the chance to provide an easy access way for users to use and pay for their service.
Furthermore, the browser could provide external connectors as well so I could have some native external app that registers a provider with the browser, allowing me to send my in browser data to an external native app (or vice versa). For example right click menu on a .drawio file and send to DrawIO or send to the currently opened Google Slide. Or send a contact from your fav web contact manager to the your native Skype app. Seriously I can think of so many uses for this! And it fits in perfectly with the existing file or clipboard apis as well.
I hope someone sees this excited rant and can make it happen! :)
I also really do hope the work that's been done in Sandstorm continues on and pushes things further for all of us. Thanks!