Exactly. Looking from the other side, I suspect Java's much more comprehensive library caused more programmers to favour it over C++ than Java's garbage collection ever did.

I think the almost symbiotic relationship between C# and the .Net libraries today is an interesting case. It seems clear that several of the language features added to C# (or the underlying .Net execution model, if you prefer) in recent years were motivated by particular ways of working with the libraries. Usually, we see mostly one-way traffic, with standard libraries trying to paper over any cracks in the underlying language.