On the contrary, the Big Tex 70CH (Big Tex Trailers 70CH Tandem Axle Car Hauler - Big Tex Trailers) weighs 1,760# in the 16’ version and 1,910# in the 18' version, a difference of 410# or 560#.You're not comparing equivalent trailers. A steel car hauler like the featherlite pictured is almost 1000 lbs heavier.
A steel decked car hauler weighs 2100 ~ 2300 lbs plus... Come on, you can't compare a wooden decked, angle iron steel trailer to what is offered by featherlite, or any of the other aluminum manufacturers.
My 18' aluminum trailer weights 1205 lbs. Is I it needed for the OP's job- probably not, but he wants to spend the money for a aluminum trailer- good for him. I have twice and have no regrets. I paid $1800 for my single axle 12' trailer and sold it 11 years later for $1600. Not sure many steel trailers would look good enough after 11 years to have that kind of resale. Will