I'll have to disagree w/ that statement. It is cheaper for them....A LOT cheaper.
It's cheaper because they switched to using African Mahogany instead of South American Mahogany. African Mahogany is heavier and a lot more dense than South American Mahogany. Also African Mahogany, the last time I checked at my local saw mill that will sell direct to public, is around $5 per board foot cheaper Than it's South American counterpart.
So LP's got heavier and heavier and Gibson's answer to all the complaints was to boar holes in the bodies. Now all the nonsense about old growth Honduran Mahogany being lighter and more resonant than the new growth stuff is a bunch of bull pucky. The age has absolutely nothing to do w/ the weight of the wood. The weight of a board will depend on the part of the tree it's cut from. The bottom half of the tree will be more compacted and dense from supporting the the top half of the tree. This is why you will find heavy and light pieces of wood through out any species of wood. The only "exception" to this is swamp ash, and that's because of the environment it grows in.
Now, OTOH, there have been more than a few that state that the old stuff sounds better than the new stuff. I don't find that to far fetched for multiple reasons. 1. Most of the rain forests that the old mahogany was harvested from was almost completely wiped out. There was and I believe still is a trade embargo banning the export of wood from those area's. 2. The environment has changed a lot over the last 50 years. I would expect both of those factors could cause a difference in sound. That's just a theory though.
In a nutshell Gibson is either to cheap or to lazy to source the good wood and have found a way to pass the buck onto their consumer base by coming up w/ the "chambers" and then have $1k to $3k up charge for their custom shop pcs. that use unchambered South American Mahogany.