Drizzt's stats are incomplete
The FRCS stats for Drizzt are most likely a 3e conversion of the earlier AD&D2e stats and don't include his most recent adventures.
In Siege of Darkness (1994) and later books, Drizzt has several magic items that are not listed in his stats. Some of the magic items include: Bracers of the Blinding Strike (usually worn on his ankles to provide Boots of Speed/Striding capabilities), a hat of disguise-type item, sometimes he has Regis' ruby gem, and other items.
Also, in Siege of Darkness, its revealed that the scimitar he took from Icingdeath's hoard is a bane weapon against Demons. So it should be a +3 Frost Bane vs. Demons Scimitar, and the bane property isn't mentioned in his stats.
Likewise, Artemis Enteri doesn't have his most recent items either.
So, I have no problem with both of them being epic level fighters, since the FRCS authors ignored the last ten or so years of their adventures (I really think the stats date back to Legacy).
Tom