TBH, a lot of people in the "Don't use cloud analytics" camp are real, real naive about how hard it is to roll your own analytics.

This is a non-trivial problem. So you see the traffic to your site. Do you have the mappings set up to geo-locate IPs by country? Are they up-to-date? How much of that traffic is noise? Do you know? What is "noise?" Do you count hits from aggregator sites? Do you count crawlers? What do crawlers look like? How do you know if your content got re-hosted?

Analytics is not a technical problem; it's a social problem. Google and the other companies that do analytics solve it with people making decisions about definitions and enforcement, not just algorithms.