They might look that way but they aren't. It's why Old growth was the choice basically forever. It's also why we make assumptions about certain kinds of wood, because historically it was old growth being mined to produce it.

Depends on species, but old growth starts in a suppressed canopy. An old growth sapling might be 200 years old before it sees sunlight. It might take 400 more years to see itself as a canopy dominant. Then it might live for an additional 200-2000 years depending on species and location.

This makes the wood incredibly dense and rot resistant. And it simply can't be recreated because it's the physical conditions that determine these qualities.

The fact is that old growth forests which are now less than 3% of what they once were, they weren't harvested. That implies they can be regenerated. They were strip mined.

I absolutely agree. Those do not look like the same type of wood at all.

The link talks about new vs old construction lumber. "New growth" vs "old growth" is very misleading in this context. It should be understood as "fast growing trees" vs "slow growing trees" ie. soft wood vs hard wood.

With that said, I am very open to the idea that trees have been breed to grow faster (and of worse quality). I believe that without having any evidence of it, but this is not that evidence.