I’d say your 95% figure is pretty spot on in my experience so far. My drive to and from work is about 40 minutes each way and normally, I would see the 3D buildings the entire way. I’m looking at it in two ways.
One way…might be a bug, because when I DO see the 3D buildings pop up…there’s a quick flicker or two.
The other way…intentional, simply because of that “95%”. So much of a drive can go by without seeing those buildings under any circumstance. I wonder if they viewed the buildings as “clutter”…?
Either way, I‘m going to type up some feedback about it. Mainly for the flicker that happens when the buildings do pop up. And it only seems to be the buildings that flicker. It doesn’t happen to the roads and it’s not the screen itself flickering.
My biggest issue with it is that by the time the buildings come into view, Maps has already moved to 2D mode since I am making my final turn(s) to my destination.
But to your point, I think it may be purposeful:
* 3D buildings have no use (typically) while routing other than they look nice. Some may say they help determine surroundings, but at the end of the day, you shouldn't be looking THAT closely at Maps while you are driving.
* To the point above, buildings DO make sense at the very beginning and end of routing to help determine location and where you are actually going...I want to see what building I am parking next to and seeing that on the map helps.
* I'm guessing Maps runs more smoothly and can make changes quicker without the graphical clutter on there...and I'm guessing this may become more important as Maps adds more detailed terrain data and while it may only be in a few large cities, I can see them adding more of the "super detail" like San Francisco has in future updates. They've already stated it is coming to CarPlay later this year.
As long as I get the street level detail they mention in features like lines, bike lanes, crosswalks, etc. I'm more than willing to give up 3D buildings while driving. And they're still there in static maps which is actually where I use them more when investigating a new area I plan on visiting.