My guess on motives from experience of running large APIs is that it’s fairly trivial to artificially inflate these numbers with bots. Which takes up much dev time for the constant battle of trying to scale to load and adjusting algos to attempt to filter out this bad data.

Assuming that’s what’s happening here, we have 3 options I see:

Nuclear option a kill the whole thing (not acceptable)
Open the data up fully and continue the fight to clean data up as much as possible. I believe despite the data being messy, there is much more value added to the community as whole having it fully open and transparent to all, and easily extendable by a powerful API. Competition is good for users and plugin devs, leading to better quality and WordPress experience.
Remove the motivation to game stats by making it only available to the plugin devs

Fully transparent numbers please, I want to know my actual install count!
Possibly later add in some more simplified public stat for users, like a growing/declining indicator arrow with %.