Hi Daniel,
Thanks for the question!
1. We are heavily invested in Pulumi ESC as it is a natural extension to manage hierarchical configs in Pulumi across stacks/projects. All your environments will be preserved when we make the product generally available.
2. The reason for it being in the preview is that we are rapidly adding new features to the product in response to customer feedback and our internal vision of where we want to be. We do not make breaking changes to the product when we add these features.
3. During preview, the product is free to use. When the product is generally available, it will have a pricing model that is competitive with the market.
Excited to see your interest in ESC! Let me know if you have any more questions.