Sam2 all those kaporos are moved to different locations on modern smooth roads and can be done on airconditioned vehicles and the claim as far as I ever heard was the supposed cruelty of swinging it over the persons head, not about how many were transported.
What changed that makes MBP so much more dangerous only now when those saying so are saying nothing about the fact that these days hospitals have an excessively high rate for causing new infections and no one is demanding hospitals be closed down.
Also many of those who are against MBP are also against bris mila at all, and say that it is “barbaric” and “mutilation”
I never heard tubes were used till modern times.
I have heard from my ravs son that he had learned that tzaddikim he learned about have said that using a tube had a lowering effect on the spiritual level of the boy the bris was done, on.