My take is that there is no such thing. This is not because there aren't tools now that do "similar things" to what HyperCard did, but there is simply no longer a personal computing environment in which such a tool fits so instrumentally and seamlessly.
HyperCard came about in an era where personal computer users were still being inculcated into what using a computer even meant. That was the moment to let end-user programming and malleable systems like HyperCard take over. (A somewhat similar thing might be said of OpenDoc, but that's a bit different)
From a corporate perspective, what even was HyperCard? A way computer users could just make their own basic applications? How do you continuously make money? What about your computer's dev community? Because of these and other commercial concerns, both the way users today engage with personal computing _and_ the tools we have to manipulate our computing environments are strongly determined by a consumption model -- and there exists a strong bifurcation between users and programmers.
We have no true HyperCard equivalent today because personal computing went in a different direction.
HyperCard came about in an era where personal computer users were still being inculcated into what using a computer even meant. That was the moment to let end-user programming and malleable systems like HyperCard take over. (A somewhat similar thing might be said of OpenDoc, but that's a bit different)
From a corporate perspective, what even was HyperCard? A way computer users could just make their own basic applications? How do you continuously make money? What about your computer's dev community? Because of these and other commercial concerns, both the way users today engage with personal computing _and_ the tools we have to manipulate our computing environments are strongly determined by a consumption model -- and there exists a strong bifurcation between users and programmers.
We have no true HyperCard equivalent today because personal computing went in a different direction.