In my experience this is not true except unless you are super genius. Most folks without PhD often keeps making same naive mistakes, for example, not studying previous state of the art, not recording experiments properly, heuristics instead of rigorous analysis and so on. PhD trains to avoid all these. It allows you to build network, identity great researchers in the field as role models and understand what scientific scrutiny entails. It is not unusual to identify paper written by someone not experienced vs someone experienced. For example, a person without PhD would often neglect to mention scale in the graphs, compute variances in findings, describe figures properly and so on. These might look minor cosmetic things but it often goes long way in overall rigor.
??? They taught all of us that in undergrad.
a person without PhD would often neglect to mention scale in the graphs
... and they taught us about the scale of a graph in secondary school ...