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.

Every port I've done to a new hardware or software platform has shaken loose at least a handful of bugs or assumptions that were well worth ironing out. And in the case of a port to Apple Silicon, you get a very fast development environment at the end of it. This library also helped with 90% of the work:

https://github.com/DLTcollab/sse2neon

Or, if you just want to create multi-arch images for your project, on your Mac...so that your non-Mac customers can use them.

I guess now it makes sense. Got 3 years to turn on ARM builds.

No, it still doesn't make sense.

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).