Further, Snowflake is a good example of an unbundled service that has more capabilities than AWS Redshift (for instance, zero copy clones). They use AWS for infrastructure - the entire warehouse is stored on S3 - and value add on top of it.
So why choose differently ?
AWS's killer feature has nothing to do with tech, it's the smooth billing process (techies choose, management pays and supervises). If you can put together a smooth process for paying for 3rd party software in your organization, you can unlock massive improvements in quality for a pittance.
I almost mentioned IAM in my post as a co-killer-feature, but I've only ever witnessed its power in AWS learning material / conferences, not being leveraged IRL, so I decided not to speculate. I'm more dev than ops, so even though I've seen a decent number of AWS environments the fact that they have all used IAM in a clumsy, coarse manner doesn't really mean much.
Do you have a feel for how frequently ops manages to actually leverage the fine-grained power features in IAM?
The issue I have with IAM is that it is not possible to be sufficiently fine grained - for example I cannot grant an instance permission to read its own tag values but not those of other instances, since the EC2 IAM API is stuck in the state of 85% done at which most AWS services eventually seem to plateau.
From my experience, Snowflake is both more performant AND cheaper than Redshift or other RDS options from AWS.