I'm surprised I got downvoted so heavily and that nobody else is concerned about this. Facebook was known for using fb platform data in its app development. Amazon could easily too. I'd rather trust a specialized analytics company rather than a company that's been known to aggressively move into adjacent industries.

Why would it be free? No AWS service started out totally free as this is.

I think this is mostly targeting people already using Amazon apps and services. I doubt we will see widespread adoption - there are so many analytics apps already, and practically all of them enable mobile tracking. Enterprises like to use the same analytics platform across everything so they don't need to maintain staff and contracts with multiple vendors.

With that said, a reason Google Analytics is free is because it let's Google track users once they leave Google and enter web-sites. Or at least Google could, by using co-relating users to search clicks. They aren't involved in the space out of the pure kindness of their hearts, and Google Analytics doubtlessly loses lots of money every quarter for Google.

"I'd rather trust a specialized analytics company" - don't. If you can, own your own data on your own server. Otherwise you will need to rent your data from your vendor constantly, or pay for a data migration process later, or pay for a data warehouse and a means to explore it.