I'm not understanding what you just posted. Are you saying that at one time estates averaged about 25% of the price of a new pipe, and that now they are 50%?
Prices on estates vary a great deal depending on how large a market of collectors there are for them. Even adjusting for inflation, some estate pipes go for more than they fetched when they were first sold.
In general, 50% to 60% is today's average pricing on pipes that aren't unicorns. But even now, some obscure pipes go for far less.
As markets mature, levels appear. Take the "vintage" tobacco market. Certain star brands or blends can go for multiples of their original release price. Every $16 dollar tin of McClelland 40th Anniversary blend I bought, now sells for $100 or more. But 15 years ago it was just old tobacco and I could, and did, buy tins of A & C Petersen Escudo for $15 to $20 a tin, as well as other old blends, and those now sell for $120 to $140 a tin.
If your argument is that estates weren't a large market until fairly recently, you're mistaken, full stop. I was buying them 30 to 40 years ago, and tobacconists had cases devoted to estates in their shops. That's not the sign of a fringe market.