Your argument is not reasonable
So you think humans will NEVER leave earth for more than 3-4 months because of a current rule? By extension do you think a Mars mission will be limited to 3-4 months because of the current rule applying to ISS (Yes Mars has an atmosphere but the radiation there is still much higher than earth)? Do you think we will never conduct asteroid missions unless they take only 3-4 months? Get real buddy! The Bush plan calls for astronauts to live on the Moon for progressively longer time frames. The 3-4 month rule must go if we are ever going to have humans explore space. OBVIOUSLY. And of course on the Moon they can use regolith for sheilding. Your argument is not logical or just plain disingenuous.