“Add to Homescreen” was available first on iOS since probably 2008. No Google service added the meta tag for it. I don’t think it was so much work at the time either, but I do think that the reasons might be the same. We need to remember that Chrome/Android arrived into that feature 5 years later.
There are a couple of problems that might get people not adding the feature, including:
- Android users might not expect apps to be in the Home Screen, but in the Application Launcher. I know, “work is in progress” for it, but I saw companies claiming that is a confusing scenario for users.
- No Share actions from a full screen experience (yes, you can still have Add to Homescreen with ‘browser’ but you won’t promote the App Banner, so…)
- Weird things still happens when people add websites to the Homescreen on Android sometimes: OAuth login, push messages, and more
- You have the icon and the browser, but if you click on a social network, you might end up in the Web View. If you click on the search result, you might end up in the in-browser experience. If you click on the icon, you get the full screen experience. Each of them with its own contexts; I think we are not yet on the best technical solution for PWA for everyone to say: “I must add this feature new on each of my web apps”. We are getting there.