This is honestly not intended to pick on C++ as a Rust fanboy, however. It really isn't.
For instance, to be a little unpolished, I would shrug off the unwrap incident as doing it the C++ way and pretending that the complexity does not need to be solved right then and there because ItShouldNotHappen or IKnowWhatIAmDoing.
I prefer Rust over C++, but I do not hate C++. This isn't even about C++ anyway.
When it comes to out of control dependency trees, I agree with you. But there is a trade off here too and that is that either you implement the thing or you externalize it. I use both approaches myself and am in no way excusing anything or attempting to be Rust's defense lawyer. There definitely seems to be a leftpad-problem brewing in the Rust community.