Merge the code, hard link the filenames to the same executable and get it to change behavior based on the name it's invoked under.
Edit: nevermind, I just learned that wget can download a page's resources or even inline them (-k apparently), that's a bit of a way off from curl's purpose. Better keep them separate tools, although wget might benefit from using libcurl so they don't have to implement lots of stuff like https or http2.