The C++ interop thing I think is massive. But isn’t there also the problem that with Rust you can’t have the equivalent of shared pointers, so you can only have a single reference to one object (sorry I don’t really know Rust, just going from how this has been described to me) which apparently makes representing things like DOMs and abstract syntax trees an absolute nightmare?
Both these constructs use the "clone" trait to iterate the reference count.
I make primarily concurrent and async applications these days so I use Arc a lot for accessing memory that is very large and shared many places, such as context.
I think the real problem is Rust has a lot of rules (that make sense for safety) that take time to understand and most people aren't patient enough to make good software because of corporate conditioning.