There are so many ways to enjoy pipe collecting and smoking. eBay offers a huge selection of estates and every now and then a truly spectacular pipe shows up for auction there. But, as has been said, most of the best stuff never goes to eBay, but is purchased through private transactions. And there are sometimes really nice pieces to be found at pipe shows.
I've bought pipes from eBay, from estate auctions, from online dealers, from shows, from carvers, and from private parties who contact me because they have something they think I might like.
What the future of the market will be is anyone's guess. Pipes could be a hot commodity or kindling. The value of "collectibles" changes, going from hero to zero, from what's hot to what's not.
While some folks think of pipes and tobaccos as an investment, I'm not one of them. For now, it's a pleasure, an area of interest, and an indulgence. I've made friends both here and abroad through our mutually shared interest and that's been an unexpected bonus. The rest of it is ultimately pretty ephemeral.