Part of AWS sells those things. AWS started 12 years after Amazon.com. Amazon has large BI orgs to build custom systems costing tens of millions of dollars.

AWS was not considered secure enough for Amazon.com critical data as of a few years ago, maybe still is not. Look at the capital one breach due to S3.

Amazon does not just give a no-limit AWS account to each of their thousands of team. In fact they are more likely to tell the team to solve it with no resources. Rival teams will want an unpopular cost savings project like this to fail so they can have more headcount and budget.

For all we know they do have this system in place. But shit happens; one weekend some Hadoop nodes lock up, bunch of associated jobs fail, and maybe it's not high on the priority list to rerun the query or investigate or the person familiar with the job is away. And so this time a bunch of fraud goes uncaught.