It's hard to guess....with more states legalizing marijuana and eventual Federal legalization; pipes may get more use than they do now. Bowl size will certainly shrink, anything above group one in size may lose value, as tobacco becomes harder and harder to purchase. Unfortunately, I think the overall outlook for tobacco use is grim, I think you will still see hand rolled cigars in 50 years, but I think any other form of tobacco will be either banned or replaced by Mary Jane. The antis are eventually going to ban cigarettes altogether, I think smokeless tobacco as in dip, chaw, snuff and Snus will be next on their agenda, then vaping. I think tinned pipe tobacco will go under the radar, by clinging to the hand rolled cigar crowd for as long as possible, but loose pipe tobacco will become harder to buy as they phase out cigarettes, the roll your own crowd has doomed all loose pipe tobacco I fear. 50 years from now I think pipe smoking, as we now know it will be relegated to geezers with big stashes, therefore all pipes will lose value, with well known brands and makers staying valuable the longest.