I'm a little bit hesitant to look too much at GA, since I don't to just make an "open source GA". In a lot of jobs I worked at we were essentially just "making a shit copy of a shit product", to put it crudely. I really want to avoid doing that.
So the way may be quite different, but the goal of providing meaningful business insights is definitely there.
The four scenarios I listed above are important to understand when running the marketing side of a B2B SaaS company.
I don't care about the implementation details (other than they're straightforward). But I need to understand that info. And today there's no obvious choice other than GA. This surprises me.
I agree that info is important, I just meant that the UI might turn out quite different from GA.