Netflix is doing the forcing. Banks are doing the forcing. There are many app categories with very little reason to exist at all, or at least not for creating dependencies on the latest client APIs.

Edit:

And it's not just that these apps are useless. In some cases they are inferior to the web app.

E.g., the Netflix iPad app can't seem to remember where I left off. It misses entire episodes. And every evening when I try to resume watching, I'm getting an error message because the old network connection is broken. Everything that's good about Netflix happens on the server. The app is just a dumb terminal and it can't even serve that purpose properly.