It is mindblowingly what the community has accomplished given the number of developers. But being more efficient doesn’t do you much good if you are massively outgunned and with clearer maintenance continuity. OffsetArrays is the wrong package to criticize here because it isn’t “really” necessary . Others are.
100%, and people get burnt - especially with AD. Some things work as advertised and are state-of-the art (e.g. SciML, JuMP, and a variety of smaller packages if you know where to find them). Others are an enormous hole chipping away at longterm usage (e.g. machine learning packages, even for niche use like scientific machine learning let alone standard ML stuff). More and more I find myself using Python frameworks because the deep-learning environment is much less infuriating and full-featured. This has nothing to do with Julia as a language, but in practice I am unlikely to switch back for those applications.