Brass Radiator vs Aluminum and Plastic?

Yes, I understand that. The question is ‘why would a brass or copper replacement tank not be reliable in modern cars over plastic and aluminum?’ The advise I was given when I asked a radiator shop about getting a brass radiator to replace the plastic and aluminum radiator that is OEM, was that brass radiators are not reliable with some modern cooling systems, like that of my Explorer. I’m just trying to get a good idea of why.

I’ve had previous problems with these plastic and aluminum radiators, and have replaced them with brass in at least three of my previous vehicles, all Japanese makes. Since I tend to keep my vehicles for extended periods of time, like my '88 Supra and '92 Celica, getting replacements that last is important to me. This same radiator man admitted that the plastic/aluminum radiators tend to only last for 7 to 10 years, which matches my experience. He was unable to tell my why the brass radiators don’t last in some applications, and I was hoping for some sort of explanation from some of the better minds on this site. Do you have any thoughts on why a brass radiator wouldn’t last in a 2000 Explorer?

I keep up with maintenance, and flush-n-fill the cooling systems every 5 years. I started doing that 10 years ago when I switched to the long-life coolants. Before then, I stuck to a two year schedule. My vehicles all call for glycol-based coolants, and I typically use Prestone.