This is something I think about, and there are some underlying technical issues as well, in coordinating all the plugins with common interfaces. We do not have workflow centric software even in the open source world which has managed to build a large family of apps in the usual mode.
Or maybe we have done it in the past(interactive software in SmallTalk), but have forgot about it.
Also, the business reasons are not prohibitive - if lot of users use the workflow model, there can be a store where they can request, raise funds for plugins with a specific functionality. Developers won't ignore it, even if the moat is weak, as there is potential revenue. It would be like consultants providing solutions rather than selling a product.
In the 1980s and 1990s there was a ton of very interesting work done on deeply thought out user-centric software designed to augment human intelligence and give people maximum control over what they were doing while still being approachable. The Smalltalk stuff was some of it, but there was some pretty spectacular stuff back in the old Windows 3.x, macOS classic, and even MS-DOS days where apps would interact richly and you had document-centric customizable work flows. You even had things like (gasp) composability of applications in GUIs.
All of this was completely abandoned and forgotten because there's no money in it. Make software like that and there's no moat, and make it local and people will pirate it. Lock it down in the cloud and lock down the data and people will pay you.
That which gets funded gets built. We get shit because we pay for shit. People won't pay for good software because the flexibility and user-centrism of good software allows them not to.
This is a very cool video. I am interested in making a dynamic notes app with user defined types and cutomizable flows. This is partly done already in Roam, AnyType... if you include the plugin system. But it seems like there is a lot of history.
Nevertheless, I am more optimistic about such a product. The key issue is building composable interfaces to which plugins can glue in.
Piracy is not such a big problem as one can give the product free of charge to users and charge for hosting or charge commercial businesses for whom piracy is not a risk worth taking.
If anything, the business implication of a ubiquitous workflow interaction is its threat to the ads model (users dont visit social media sites but read in data via apis). The ad model might need to be replaced by something like micropayments to content creators, but that is a distant issue.
Or maybe we have done it in the past(interactive software in SmallTalk), but have forgot about it.
Also, the business reasons are not prohibitive - if lot of users use the workflow model, there can be a store where they can request, raise funds for plugins with a specific functionality. Developers won't ignore it, even if the moat is weak, as there is potential revenue. It would be like consultants providing solutions rather than selling a product.