I mean yeah, there are tools to automate it. I think you may have a point if both of the following hold true:

1. You very frequently have to install your setup from scratch.

2. Preconfiguring something that aids in installing from scratch is not viable or sensible. (Perhaps you work in an environment where you're not allowed access to your personal dotfiles repo, for example.)

But I think most people will fail at least one of these checks.