Yeah, that was well sourced on the research front.
Look, I'm not a fan of extrinsic motivational strategies (I'm a MS teacher, so I have some familiarity with the actual science), but a "participation" trophy, at least as I've experienced them as both an athlete (in the 70s/80s) and as a parent (this century), is generally a tangible reminder of actual effort and accomplishment. They go away at the point where they don't function in that manner anyway, for the most part, and the kids who are going to keep playing the game quit caring about them (when the don't represent something real, like a championship) pretty early on.
I guess at the end of the day, I think it's a lot less about the trophies and lot more about coach/parental attitudes/expectations.