Bill Atkinson made a shape, not an app.
HyperCard came with my Mac in the 90's. I made stacks about school stuff. And consumed lots of other people's stacks.
It changed me, and I think it changed a lot of people who don't realise that's what changed them. The web is a HyperCard descendant. Wikipedia is a HyperCard descendant. The hyperlink is a HyperCard descendant. Bill Atkinson made a shape and the shape ate the world.
What got lost on the way is the bordered rectangle. The thing that says: here is one card, here is what's on it, here is where you can go from here. Modern websites are scrolls, and the bordered rectangle is reduced to a "hero section" or a "feature card" or one of a thousand other things that aren't cards.
Bill Atkinson didn't invent stacking documents. He invented a shape that made it obvious you could.