I'm not sure what you mean by engines designed for long life coolant. EGR (not new) design means coolant is more critical.
The new "extended life" antifreezes are the same as conventional antifreezes except for their corrosion inhibitors.
I agree there may be no valid reason to change it at 30k miles but if you don't mind getting your hands dirty or have it done for you it is in no way false economy.
(getting off soapbox here)
