A lot of packages are pulled in to call minimal bits of the actual library. I obviously don't have any statistics on this but my instinct would say that for the average application only 5% of an average package is actually used.
replySo not running package installation scripts is a huge, massive problem.
So what? Packages can just put their backdoors in some initialisation code that is always used.
replyIt is possible that not running package installation scripts could improve security, but for that you need really good sandboxing/compartmentalisation of library code, e.g. with CHERI, WASI component model, or if all of your code must run in a secure context it probably helps.
But those situations are unfortunately rare in my experience.