Thank you! The previous Dart backend attempts were predating Flutter, so the conditions are very different now. Serverpod is also a funded company, and not a side or hobby project like earlier Dart servers.
The main plan is to provide hosting for Serverpod. It's still an open-source project, so you can always host it yourself or on the cloud platform of your choice.
I have not seen any niche companies having success with that business model
Our own surveys show, that enterprise users want to host on a platform of their choice. They are not too eager to switch providers and are more unlikely to use your software if it doesn’t run on AWS
Knowing that, if you want to capture enterprise users, you should offer a managed version of your product on AWS or GCP
A company does not need to reach Amazon size to be viable, despite what all the VCs try to hammer in your mind. A 20M revenue company is perfectly fine. So is a 2M one, or even a 200k one.