Good integration always provides the best user experience and you need an app to best integrate into someone's phone to provide push notifications, use quick reply type, etc; really to make sure of a phone in the most efficient way possible right now it just has to be an app and I don't see that changing anytime soon.
But look at the apps you mention that you do use: "gmail, maps, messenger, calendar, contacts, and web browser (chrome)"
Windows Phone doesn't have Google Maps so the navigation and overall map experience isn't as good. It doesn't have Chrome so you can't share your bookmarks between all your devices. Without dedicated Google apps it's harder to take full advantage of Google services.
[1] http://www.nielsen.com/us/en/insights/news/2015/so-many-apps...
I'm not sure how true this is. You need some apps, to be sure. But I own an Android phone had have installed less than half-a-dozen apps that it did not come with out of the box.
I use gmail, maps, messenger, calendar, contacts, and web browser (chrome). That's 95% of my phone usage.
I wonder how many users there are that don't play games or use a lot of social media apps. I'd guess a fair number in the 30+ age group. But maybe most of them have stayed with feature phones.