I found the whole cabal experience confusing and not well documented. I kept finding blogs online that were not working anymore in my version of cabal ('cabal sandbox init', 'cabal init --sandbox'...) when looking for advice. I still don't understand the whole v1-build, v2-build, new-build and build... The manual doesn't seem to have a decent conceptual overview of what the tool should do (e.g. an explanation of what sandboxing is supposed to achieve, or the 4 build command versions). Several of the links on this page https://www.haskell.org/cabal/ are dead https://www.haskell.org/cabal/release/cabal-latest/doc/API/Cabal/ or refer to old versions: https://wiki.haskell.org/Upgrading_packages This should not be construed as a critique of what has been achieved, but as honest feedback of my experience.
Innovation and advancing comes after competition, why shouldn't we embrace that wrt the tooling of Haskell? Duplication in efforts is a relative smaller problem IMHO. Well the competition has "go build" and cargo... And duplication of effort is a problem when there's not enough resources for even one decent build tool Immanuel