It’s specific to individual leverages, strengths and weaknesses, and the like. We have 132 lb lifters pulling 4x body weight.Maybe a good question is: at what point improving the lifted weight relative to bodyweight becomes too difficult?
For instance, as far as I know, deadlifting more than 2.5 BW is not easy, and is not common. So my guess is that after 2xBW, or close to 2.5 BW, the easiest way to improve the lift is to get bigger.
-S-