Right. The problem that has arisen is creating that mapping between those HTTP urls and the app URL, especially since only the app developer knows that URL and how it is interpreted inside the app, is almost non-existent. What has resulted is a shadow set of URLs which only work if the app is installed (which you can't tell from the web). All the great network effects you get from hyperlinks on the web don't get passed over to the mobile ecosystem because of these properties (hidden URL structure, inconsistent with the web, etc.).

When YouTube came pre-installed on iOS in the first few versions, when you clicked on an (HTTP) link to YouTube it would open the app. It was a great experience because the YouTube app had a nicer experience than the web. It would be great to be able to do this for more apps, if those apps wanted it.