Isn't it bunk to apply extrapolation to two countries that start from a different per capita base?

Germany is significantly lower in per capita emissions so their reduction is (I'm assuming) a lot harder to achieve. It's like comparing fat loss between someone who starts overweight vs someone who is starting neutral bmi.

https://ourworldindata.org/co2/country/united-states?country... and add Germany.

Happy to hear why I'm wrong, I'm certainly not an expert in stats or emissions.