As an interested parent (although of a 4 yr old), did she get bored because she hit a wall in what she wanted to do? With HTML its fairly easy to generate a nonlinear text and image based story, but I imagine trying to add any sort of interactivity through the mess of CSS and JavaScript might quickly lead to frustration. Unlike HyperCard, today's technologies don't seem to have a smooth learning curve as you try and build more complex things.
No she just got bored because that's her. HTML can have a smooth learning curve but its not baked-in so you need someone to manually guide them and since most adults don't know how to do this that's a problem. My point is it is solvable, not inherent.
