It doesn't take an Electrical Engineer. It takes some small research and knowing how to read.
Fact is a 20-30 Amp wire will not support 150,000 amps.!
I have an M.S. in EE. You are correct.
Actually, that wire should instantly vaporize or at least melt if it did attempt to carry most of that energy. And then where would the rest of the energy of that strike go?
You can use #26 AWG wire as long as it is also 1.5" wide. But most building codes don't recognize that, so you have to use 1/2" braided copper wire, give or take 1/16".