Consider how you trust using dbt more than rolling your own transformation tool. Why wouldn't this apply to the rest of your stack? The 10+ companies that offer data extraction and loading are likely a better choice. Again with Analytics - the dozens of companies that offer BI tools are probably going to be the better choice.
Maybe you can build all these tools better than the hundreds of companies with thousands of employees and millions of dollars. It just seems like the odds that you build the best of each is so unlikely.
I would have been more impressed if your team had designed some API that other tools/platforms could plug in to coordinate a lot of the above jobs with your CI system. There is a SERIOUS need for that and I've had a lot of conversations with companies about what that would look like.
To answer your quest, no, Fivetran does not currently belong in the orchestration area, IMO. I've heard they are soon to release some sort of orchestration tooling to compete with dbt, but it isn't the type of orchestration you get with Airflow.