Though it's not the only answer, it's a very good one. I think a lot of us, who played in the 80's, went from a trusty Mali, moved up to maybe a decent Meucci, and then on to the ultimate "Schon." But these days with the internet and all you can find a lot of really decent custom cues for the 1000.00 price range. And a lot of people, even in this generation, when coming out of that entry-level cue range move on to the premium high-end production cue before they take the leap to full-on custom.
That and Schon has done exceptionally well with regards to their name. They found a way to make a production cue collectible. They don't just make one "cue of the year" limited to 300 pieces like McDermott, they make an endless supply of limited production cues. And by limited I don't mean to 300, but more like 15 or even 7.
I think, for aftermarket value, you can do better making 10 cues limited to 15 of each than you can simply making one cue at 150 pcs.
Schon has built a name and a reputation that has stood the test of time.
There are thousands out there due to the fact they have been around for decades. And they keep their value because most of them are short-run and literally made to be an instant collectible.
And for me, 43 years old, the name "Schon" brings back the days when I could not afford one in the 80's. Only the rich had Schons, I had my plane jane Mali. lol
That, and as also stated previously, supply and demand. This is one product who's supply may be massive, but the demand never really evaporated for this brand.
Simply put, it's a "gateway cue."