Family heirloom furniture - mahogany and mahogany-looking "antiques", handed down for a couple of generations, have declined in value over recent decades to the point where you have to pay somebody to take it away. Even the high-quality stuff from 1850-20th C.
American antique or semi-antique (ie "old") "country-style" furniture still retains some modest value, but it is not usually brown.
There is no market for "brown furniture" anymore, and the experts say that your kids will never want it either - even if they ever have room for it. If you want or need to de-clutter your home or homes, the best deal might be to donate it to a charity rather than paying $600 for somebody to take it away.
Today's precious thing is tomorrow's junk. I still like some brown antiques if over 200 years old, but a room usually can't handle more than one.
Why the Market for Heirloom and Secondhand Furniture Has Disappeared
Somewhat related, are you too attached to your stuff?