I agree with everything you have said.
I also think that is something specific to the USA. There are countries that push out better lower weights because it suits their team makeup and there are those who push out better upper weights for the same reasoning.
If 55 KG was still the weight class (it is for MGR, fwiw), for MFS, then you'd see the major players still making that weight with very little issue (Russia/Iran/Japan, etc.). The USA is bigger than other countries on average, and it really isn't that close.