> its syntax

I haven’t used rust, but having gotten used to C and C++ at a time, I expect that would happen with rust, too, if I started using it. Because of that, I think this is just a matter of familiarity.

> polymorphism based on monomorphization

Implementation detail (yes, there is only one implementation at the moment, but this means it can be changed without changing the language)

> the requirement for many dependencies to get anything done

Fixable if a party is willing to write or package together a fairly large set of dependencies into a single package.

> an ecosystem susceptible to supply-chain attacks

Fixable if that party is trustworthy. Also, for which languages is this less of a problem? You either have third-party libraries and a potential security problem, or you don’t, and need to write more code.