It seems like Google exploded pretty quickly, so I bet there were a lot of disconnected apps being developed at the same time. I think as they continue growing they realize that some apps duplicate features, or have features that may be better served from other, bigger apps (in this case, maps may be better suited for some of trips' features).
I worked at Intuit for a bit, and with only a handful of products they were experiencing the same thing. I can only imagine trying to coordinate so many teams across such an enormous organization.
The platform you develop on isn't a feature. It's a platform - and without a doubt, a web app is the most ubiquitous kind of app that can serve anyone on practically any internet-connected device.
Internet-connected is the key term here, though. If your target audience are internet-less note takers, then a desktop app is the correct choice.
I worked at Intuit for a bit, and with only a handful of products they were experiencing the same thing. I can only imagine trying to coordinate so many teams across such an enormous organization.