Off topic:

I'm tending towards the opposite, with stuff like plastic or metal, those things are a little more durable and will last longer. Granted, non-stainless metals may corrode or rust, but even then it will take a long time if they are thick enough. Sunken ships at the bottom of the ocean have been rusting for decades or centuries.

Wood will last and is strong enough, but untreated it will degrade faster than concrete or metal. Specifically for resistance training, I prefer free weights over stuff like giant rubber bands. Dumbells. Barbells. Cast iron plates. I mean, if you do Olympic style lifting, then bumper plates would be for you. They just won't last as long as metal plates. I'm still going to make a wood flat bench and wood squat stands, they'll be good enough for several years.