From a manufacturing perspective, it’s as real as the ocean is wet.The lumber shortage is artificial if it exists at all. I don't buy that excuse for a second.
The sawmills might be stocked to the roof with fully cut lumber ready to ship, but all of the lumber yards in my neck of the woods have some racks at a quarter their typical capacity and some racks empty.
My company is waitlisted for birch 1” ply,
The shortage might very well be manufactured.