@gatsbyjs @presentday @Netlify Cache management is tricky so we simplify it for you by not exposing cache controls between the immutable, atomic builds.
but... there is a way to manually cache things between builds on @Netlify. Just be careful!
@stefanjudis of @contentful blogged it:
https://www.contentful.com/blog/2018/05/17/faster-static-site-builds-part-one-process-only-what-you-need/