The US national average grid loss is about 5%, which I figured would often be more than made up for by a lack of shadeing at larger installations. While grid losses are likely to increase as we move to renewables, that’s down to the fact that prime solar and wind spots tend to be much farther away from major north American cities than the suburban power plants that feed them currently. Given the density of said cities, rooftop solar just takes to much space to provide the necessary power for a taller building.

While you can find some home scale ones with sun tracking, given the weight and foundation requirements they almost always need to be built on the ground, and do cost even more. You also have the aesthetic constraint, as while panels flat against the roof only annoy the most Nimby of Nimbys, large person sized poles like this are harder to hide, even if i think they look neat crystal flowers.

https://www.solarreviews.com/content/images/blog/post/focus_images/41_Dual-Axis-Solar-Tracker-2-970.jpg

Finally, tracking panels do have higher routine maintenance requirements, as there are now parfs that can move, wear, and jam. It doesn’t happen often, so one technician can dozens of square miles by themselves, but it takes a lot more time when you need to schedule around individual homeowners and a wide array of different types of install as compared to see a notification on the monitoring software when you get into work, hop in truck with a set of standerd replacement parts, go to panel and fix.