>>10956263Doing a PhD for the money is the biggest meme. There may be a few jobs that require a PhD, but outside of those you're almost certainly better with the equivalent years in work experience than a research degree.
Your parents aren't entirely wrong about things though as entry into PhD positions is also very dependent on your undergrad GPA.
Research experience is what makes your application stand out. Usually people have very limited research experience coming into a PhD, in much of the world it's common to have done some as part of a Master's project but this probably doesn't apply to the US. They won't expect you to be a first author on a Nature article (or even to have any actual publication history), just showing that you've gone beyond what was mandatory to get involved with research is good. The point of a PhD is to make you into a researcher, it is not expected that you have the full skill set already, rather just the drive and ability to be an independent researcher by the time your years are up.
To this end, getting involved with a research group for a research project over a summer holiday or similar is a good idea. I'm not sure about whether this research project would happen while you're doing your undergrad, but if not then it's probably not worth it to take an extra year between graduating and applying just for that.