Because people like low cost stuff. You can buy formaldehyde free plywood and MDF, but wow it's expensive compared to the formaldehyde containing products!
Vinyl flooring that has become very, very popular recently is probably worse than wood composites with regards to air quality and overall toxic effects.
Unfortunately, a lot of the effects from these materials aren't immediate and typically don't affect a large portion of the population, so it can be hard to get people to realize it's bad on a large scale.
There has been more of a focus on indoor air quality over the last decade, I expect that to continue and that we'll see more of a push for materials that have better air quality properties.
Vinyl flooring that has become very, very popular recently is probably worse than wood composites with regards to air quality and overall toxic effects.
Unfortunately, a lot of the effects from these materials aren't immediate and typically don't affect a large portion of the population, so it can be hard to get people to realize it's bad on a large scale.
There has been more of a focus on indoor air quality over the last decade, I expect that to continue and that we'll see more of a push for materials that have better air quality properties.