Now that you mention it maps hasn't really improved since streetview. Search is worse. Gmail hasn't really changed much. I guess after it's launched new features are too difficult to add for google.
Recommend taking a look at this blog post: https://www.justinobeirne.com/google-maps-moat the author has updated a couple times. The changes are subtle and are amazing for your benefit. Not seeing the change is them getting better at easing you into the new functionality, not them stagnating.
Building new stuff is always more attractive to engineers than maintaining and incrementally improving existing stuff. Google suffers from this problem somewhat worse than most companies, where its best engineers jump to new projects and the existing products languish because it's not attractive to work on.
The Apple Maps 'street view' equivalent (coming in iOS 13) has a transition animation (for moving down the street) that absolutely knocks the socks off Google's. It was surprising to see just how strikingly better it is. I don't think Google changed it in that time.
