The problem though is that if you eliminate the markers of credentials any field of information gets flooded with many people who don't have the requisite knowl

The problem though is that if you eliminate the markers of credentials any field of information gets flooded with many people who don't have the requisite knowledge to be talking about said field in the first place. While you could make the argument that any investigation into this bogus research would reveal that the person is unreliable, in reality, doing such an investigation is incredibly time consuming. It's much more efficient to take a Ph.D or any other specific credential as a filter and make the general assumption that someone with that credential is more likely to be correct and have valid research. Yeah, that assumption can and has been way wrong in the past, but I would argue that the valid/invalid ratio compared against the time needed to fully investigate every bit of research any person puts out is much preferred.