> I don't think the concern is 'how long does deployment take' but 'how fast can we iterate?
And for iteration, the only thing that matters is the size of the top layers that are being iterated on. Not the overall image size itself.
You can put `RUN apt-get [kitchen sink]` at the beginning of the Dockerfile and it pretty much won't matter. When you change anything in the project repository, that bigass giant base layer doesn't get re-pulled because it doesn't change.
To validate that a layer, Docker daemon just compares the hashes. So, for unmodified layers, docker pull is constant time with image size. The Docker daemon only downloads from the registry starting with the bottom-most modified layer relative to its cache.
If anything, throwing the kitchen sink in the base layer is better for fast iteration. When you're being parsimonious about third-party libraries and packages, you'll frequently have to rebuild the base image. If you `RUN apt-get [everything]`, then you'll hardly ever never need to rebuild/re-push/re-pull that layer, because you'll always have whatever you need already available.