I think it really depends on the bottom Group9. For a sand, firm mud type bottom with little or no rocks, thick weeds or other debris, then it's hard to beat a good Danforth or Fortress for that matter. But for other harder, chunkier or obstructed bottoms, a good plow works much better. I used to routinely deploy both (one or the other) depending on the bottom I was anchoring in while on the Great Lakes.
Since moving to a Rocna I almost never deploy anything else. In my opinion (flame vest on) the new style anchors cover pretty much the same range of bottoms as my Danforth/CQR used to. But I still carry a large Danforth, a Bruce, a large (storm) Fortresss, in addition to my Rocna which is my bower.
Your comment about commercial fishermen all using Danforths is no doubt true. I'll have to observe what our Great Lakes boats carry. However, if I may be so bold, these boats are likely not anchoring very much. They're working, or they're in port. I bet their anchors are more for show to meet legal requirements.