[stephenr]

None of those OSS relational DBs offer Amazon lock-in the way DynamoDB does - it's more reliable income if someone uses it, but it also takes more convincing for people to use it. What enterprise would use it if Amazon themselves don't?.

[staticassertion]

This argument makes no sense at all. What does lock in have to do with Amazon dog fooding its services? They're... trying to lock themselves in? What?

[stephenr]

Amazon owns Dynamo DB, and make it available via AWS. If customers use it for non-trivial applications, they have some degree of lock-in, because they can't just migrate to another (self-)hosted instance of e.g. Postgres, MySQL, Oracle, Mongo, what have you.

So Dynamo is an opportunity for Amazon to generate lock-in through their own proprietary software.

But big and likely even medium size businesses are less likely (compared to tiny companies that barely go above the free threshold) to use a new technology without any big well known users, or publicly documented use-cases etc.

One big way companies can provide some confidence to potential customers about their technology is by dogfooding: they use the thing they're trying to "sell" (regardless of whether it's a licence, a service, whatever).