I have had xboxes dating back to the original (core) system; I've never had a single disk eaten...
Let me guess, you stand yours up vs laying it down... Where you CAN do that, it's not really recommended...
And you can buy a disk resurfacer and not have to buy new disks... or a squaretrade warranty i think even covers games for like $10...
They do make pads to install in the dvd drive (though that involves opening the xbox which voids your warranty) that make it so that they don't spin freely when you set the xboxes on their ends.
Still prefer the xbox to my old ps3 lol
