The answer lies in PSA 10 RCs of Maddux and others. Leaf is sort of seen now similarly to Topps Tiffany: same card with a much smaller print run. So people who collect HOF rookies would rather have a top graded Leaf than the base Topps.
https://www.psacard.com/auctionprice...summary/236746
PSA 10 Greg Maddux: $728 Leaf, $202 Donruss
PSA 10 Barry Bonds: $4000 Leaf, $200 Donruss
PSA 10 McGwire: $1000 Leaf, $100 Donruss
PSA 10 Bo: $500 Leaf, $200 Donruss
So the unopened is much higher.