But Docker images don't necessarily have ARM64 support. If you are exclusively targeting x64 servers, it rarely makes sense to support both ARM64 and AMD64 platforms for development environment/tests, especially if the product/app is non-trivial.
And it looks like Rosetta 2 for containers will continue to be supported past macOS 28 just fine. It's Rosetta 2 for Mac apps that's being phased out, and not even all of that (they'll keep it for games that don't need macOs frameworks to be kept around in Intel format).