Been watching this thread from the start and compelled to vent! Save the world bs they say.
Alu is cheaper to make, it suits manufacturers for more profit. If it lasts a a few years the aftermarket industry is more than happy.
I have had two alu radiators with plastic tops on other cars just pop or crack not lasting 5 years. Without warning. Not even off road.
My 1988 hj75 copper radiator is still the original and it gets a work out with vibrations on bad roads, and heat, and towing or hauling heavy loads regularly. Solid.
No comparison in quality or longevity. If you can get a good copper and brass radiator, it is worth it. Perhaps even custom made, $$$ but for the peace of mind. Especially if you go remote..