I would bet there was volumes of scientific evidence to support that claim ;)
What it would do is increase the mass the element would need to heat. I'm not sure about the premature failure, but it would take longer to come up to temp, and longer to cool down.
Solder tips were the high volume items, not the heating element.
They were simple copper or steel tips with little or no cladding; they would be eaten away pretty quickly.
On my old Weller guns, I don't even bother to buy tips anymore, I just strip a piece of left over #12 Solid. They seem to last as long ;)
The controlled 40W Station is still using the same tip it had when I got it 15 years ago.
, Ron WB9YZU