Building a tokamak fusion power plant is not a scientific problem, but an engineering one.
The science works and says for a stable plasma with the temperature & density gradients at the edge manageable, then the device needs to be very big. ITER is just about the smallest size that can achieve Q>1.
Just because the first ‘candle’ of fusion needs to operate on a scale larger than our everyday human interactions should not surprise us. Its still a lot smaller than the Sun.
