The article suggests an answer:

"The viability of our company, Timescale, is 100% dependent on the quality of TimescaleDB. If we build a sub-par product, we cease to exist. Amazon Timestream is just another of the 200+ services that Amazon is developing. Regardless of the quality of Amazon Timestream, that team will still be supported by the rest of Amazon’s business – and if the product gets shut down, that team will find homes elsewhere within the larger company."

Breadth versus depth seems to be the play outside of their absolute core offerings. It allows people to dip their toes into something with minimal commitment and by the time they realize the shortcomings they might conclude that migrating for those features just isn't worth it.

So this give them a bit of lock-in. Come for the EC2, stay for the minimally viable queues, machine learning, containers, etc.

This exactly, they are just trying to get their foot in the door in literally any idea someone else is already pursuing so that if it starts to make money they can start to put the juice on the engineering for that and take their market share.

The business model is solely focused on competing with and taking out other businesses, not actually providing any value. AWS is like a pack of sharks.

The value they sell is really operational convenience. Over time they have figured out how to run large services at scale, and monetize that. The features of those services are often weaker than competition, as noted in this thread.

There are only so many "A" teams in a big company.