Some of it's better quality metals, too. Very hard to get crisp details out of stuff cast in the lead alloys that were the norm prior to - was it the early 90s? Very, very late 80s? Whenever the "lead ban" panic due to California legislation started up. I remember the FLGS organizing a protest group to fight similar legislation here in New York, and Ral Partha introducing "Ralidium" as their new lead-free alloy. You could tell their casters were struggling with that stuff early on (overcooked, discolored and often super brittle) but in the end we wound up with sharper details, lighter figs, and a general improvement in sculpting and casting quality.