R does have namespaces. Take a look at the NAMESPACE file found at the root of every R package, which defines the symbols and methods exported by the package.
> which defines the symbols and methods exported by the package
Which are all dumped into the one single global namespace regardless if you want everything or not.
I can't remember the exact number, but tidyverse package imports literally thousands of things into your global namespace on package load, coupled with any other dependencies and you have a hell of a time figuring out where any function or constant came from.
Note for many R packages, the NAMESPACE file is autogenerated from roxygen docs: https://cran.r-project.org/web/packages/roxygen2/vignettes/n...