But it isn't what I meant. A HyperCard reboot would be a modern GUI builder with a deck-of-cards drag-drop metaphor, deployable as desktop, browser, and mobile apps for any platform. Mobile poses some problems, particularly iOS, but I don't think those are unsurmountable.
Decker is a love letter to the HyperCard which was. But if HyperCard had survived as a product, today's version wouldn't look anything like that.