Great question! We specifically started with connectors/plugins to cloud infrastructure providers and other infrastructure vendors - This is why most of our users migrated and/or compared us to the tools specified here (https://www.cloudquery.io/docs/cq-vs-others/overview).
There are no connectors for AWS, GCP, Azure in FiveTran, Airbyte, Meltano but as we extend the number of our source plugins I believe this question will come up more and we will add those products as well to our comparison list.
Interesting. We will take a look at this even though we usually build our own connectors due the huge concurrency/speed advantages when using CloudQuery SDK.