The thing is that even on a simple site with html and css while creating it there might be issues that you can quickly catch something that assists you... tools. The page looks broken? Oh, being able to lint that html or css will quickly find any issues stemming from that but hey those are tools to introduce. Not a build tool as in generating an artifact in this case but often checking is part of that pipeline to avoid errors.

I agree that it's gotten pretty crazy for certain things over the years but there's a good balance in there somewhere and it's only natural to advance technologically speaking with the addition of tools.