I believe you that cheap lumber has always been bad.

The top and the bottom aren’t going to change. They CAN’T change. It’s physically and logically impossible for them to change.

I live in BC where forestry is a big part of the economy. As i understands it, there is a big difference in log quality between old growth fiber and second growth fiber. It’s because old growth trees grew in forests and second growth trees grew in fields (initially).

Trees grow towards light. Forests are shady so trees grow slowly and pretty much straight up. Fields are bright so light is everywhere and trees grow quickly in every direction. Therefore old growth trees have fewer knots, and tighter, straighter grain where second growth has more knots, and fat rings with more twist.

Also because of improved distribution infrastructure the cost of shipping crappy wood to a market where people don’t know any better has gone down. Also if you live in an area with historically good wood supply, it’s also easier for the good stuff to be sold into other markets too.

Also, because everybody tried to build a new deck at the same time (during the pandemic) quality control may be more lax now because they know it will sell anyway.

Here is a quick visual comparison between old growth and second growth forests. The video more from an ecological perspective but it gives a good view of the difference between an old growth forest and a replanted forest.

There are a lot of differences between old growth and new growth wood that could at least partially account for your colleagues’ opinion.

Another thing that’s potentially changed is who they’re buying their wood from. Buying it from an orange hardware store vs from an actual building supplies store could make a big difference.