This whole conversation started with you saying why abandon GA when you can use it without compromising clients' privacy. An exchange that followed shows that one can't actually derive not just the same function from GA that way, but virtually any function at all. Yes, you can feed data in, but the usefulness of what you can get back out is next to zero. What am I missing?

From your opening comment:

> Why not move to push GA data server-side?

Because it renders GA largely useless if clients' privacy is actually observed.