That's a bold claim. Do you have any references to support it? The examples in Docker's documentation use apt-get directly and I don't see any recommendation to use a base image as you describe.[1][2]
With Debian, there are snapshot images[3] which seem like a better approach for making apt-get reproducible. You'd simply have to change the "FROM" line in the Dockerfile to something like "FROM debian/snapshot:stable-20220316" (where 20220316 is the date of the image you are trying to reproduce, helpfully given in /etc/apt/sources.list).
With the approach you describe, you would have to carefully manage the base images: tag them, record which one was used to create each application image, and keep them around in order to reproduce older application images.
I'm sure there are situations where the approach you describe is useful (e.g. with other package managers, especially ones that don't have a notion of lockfiles), but it adds complexity and I don't think it's necessarily justified in the case of apt-get (at least on Debian).
With Debian, there are snapshot images[3] which seem like a better approach for making apt-get reproducible. You'd simply have to change the "FROM" line in the Dockerfile to something like "FROM debian/snapshot:stable-20220316" (where 20220316 is the date of the image you are trying to reproduce, helpfully given in /etc/apt/sources.list).
With the approach you describe, you would have to carefully manage the base images: tag them, record which one was used to create each application image, and keep them around in order to reproduce older application images.
I'm sure there are situations where the approach you describe is useful (e.g. with other package managers, especially ones that don't have a notion of lockfiles), but it adds complexity and I don't think it's necessarily justified in the case of apt-get (at least on Debian).
[1]: https://docs.docker.com/engine/reference/builder/#exec-form-...
[2]: https://docs.docker.com/develop/develop-images/dockerfile_be...
[3]: https://hub.docker.com/r/debian/snapshot