And when a bug is found, instead of fixing it in one place once, you now have to hope that all of your deps and all of their deps update themselves appropriately.
Which is great if you are one person and you fix the bug in your own code. What you're ignoring is that if everyone writes their own version, then the same problem exists. That bug has to be fixed across every (buggy) implementation. A well-defined dependency system where it is easy to discover and update to a new version isn't a matter of hope.
