Think about that for a bit.
Now you might think that a gas guzzling 4.8 litre car can never be environmentally friendly, but just think about that stat for a bit. What they're saying is that 60% of the stuff we've made is so desirable, so well put together, so well designed, that people are still using them.
Imagine if 60% of other stuff was still in use. I don't know about you, but I'd be happy if 60% of the iPods I'd owned were still working.
Imagine if 60% of carrier bags were still being used. Imagine if 60% of computers were still in use today. 60% of food packaging was still in use.
Lewis Mumford, the historian said "Why should we so gratuitously assume, as we constantly do, that the mere existence of a mechanism for manifolding or of mass production carries with it an obligation to use it to the fullest capacity?"
Or why do constantly we make as much stuff as we can, rather than as much stuff as we need?"