This is especially one of the glaring holes with web apps in relation to their native counterparts. There just isn't a central destination for users to easily assess and access them. If web developers can come together and make this happen on a greater and more open scale than what the App Store, Chrome Store, or any other restricted app directory is currently offering, then the web has a chance at reengaging those native app users. Until then, the web is a jungle.
Updates are a major issue. Most web-spoilt users don't even understand why apps don't update themselves. Browser functions are useful in most apps, hence the 'back' buttons in the top bar of most iOS apps. People are used to the web nowadays and expect similar functionality from the rest of the software they use.
Discoverability is a big problem. The chrome web store is an example, it's interesting, but it's only built into chrome, and we had too many failed "Web directory" projects in the past anyway. There are other routes, like facebook viral apps, but these are also siloed.
The typical user doesn't care about updates. Most iPhones I see have 15+ uninstalled updates. The response to every Facebook update shows that that the typical user will resist change. Why would silent updates be critical to these kinds of people? I can about what version they are on as a developer but they don't care.
The back button is useful to some apps, some of the time. Why should you show it all the time and confuse users? Native back buttons also allow you to show context; you can display information about where the back button takes you.
- Web app discoverability is much worse
- Updates is a minor issue for users
- App development is not the user's concern
- App store approval is a net win for users. It eases their concerns about malware.
- Browser functions are not useful in most apps and the add an extra layer of abstraction
Native app can be made into just fine web apps but that is not always good enough. The best apps are still native.