There is an absolute dearth of tools, especially modern ones, in this space, but the tools to generate call graphs have existed for quite a while. Egypt will parse output from gcc and output a dot file for gnuplot/Graphviz. There may also be D3.js support in places.

I agree we need visual tools, especially when trying to maintain a large codebase, but only the largest companies can sponsor development of an in-house tool for their codebase, and many of them won't. Maintaining code isn't sexy and doesn't make for new features to sell.