Very true. I have had similar experiences with gear from various manufacturers.

That being said, it is possible to get some real bargains (on good stuff) at thrift stores and garage sales. My wife found a very nice down jacket, nearly new and from a good manufacturer at a thrift store. I forget what she paid for it but it was peanuts compared to the original price. She once found a nice, three season down sleeping bag at a garage sale for a very few bucks.

I suppose it helps if you do your thrift store and garage sale shopping in an area where lots of people own outdoor gear. And the gear you find probably depends somewhat on the region. I would guess one wouldn't find too many down jackets at Florida thrift stores? But Florida might be a great place to look for used diving gear?