I remember those little, lightweight, plastic headphones with the Yellow foam earpads that were so different than any other headphones out there in the 70's. You could actually listen for hours without your ears sweating.
They were definitely innovators. End of an era, but change is a constant.
BTW, those cabinets will easily last 100 years. And will only get better looking with age and use. If some future owner were to ever replace them, it'd be a damn shame. I'd take them with me if you ever move!
Consider yourself employed for several years if I ever win the lottery!
The prices on Baltic Birch plywood are very regional. I was paying $50 a sheet in Alaska in the mid 90's. It's still going for around $20 a sheet in South Texas. Here in the bay area it ranges from around $60 - $90.