Well then you and plenty of other people have some wrong ideas about package.json. That isn't surprising.
package.json gets rewritten for all kinds of things, which is not really compatible with adding comments wherever you want. Adding "why this dependency is here" comments may seem like a good idea to add to package.json, but you're kind of missing the point. If you need that level of documentation, trying to shoehorn it into package.json is just the wrong place for it. Soon enough your package.json looks like a graffiti wall.
>To be blunt, then, I can't believe you've ever written any code in a business (i.e. with multiple developers) in the Node/NPM ecosystem.
Then you'll be astonished that I have been working with nodejs for about 14 years professionally. Sure I have wanted to put comments into package.json, but I was naive and now I'm fine not doing that. I haven't wanted to in many years. I document things in other ways and it has served us all very well. YMMV.