As an iOS developer I can tell you that programming the native app does not take that much time either.
The complicated part was, I think, to come up with the concept. Clear is having all this success not because is a complicated app full of features, but because it's simple and with interesting concepts that nobody used yet. The app itself is pretty simple to code.
The HTML5 app is also incomplete and very buggy. I think it's not surprising that the more complex gestures are missing (such as pinch for new item). Additionally it took me about 1 minute to get it into a weird broken state (permanently pulled down). Not saying all this can't be fixed, just saying that assuming 1 week development time and calling it demoware may be more than a little unfair. I seem ro hear that a lot about things and then the only proof you end up seeing is some 80% mockup (billed as a complete reimplenetation) that leaves a lot to be desired.
