Keeping PS2 selling is helping their bottom line immensely.
Instead of selling a system at a loss, sell one at a gain.
But it's the absolute worst move they could make for maintaining PS2 software sales, which is where the real money is. It also takes away the major incentive for PS2 owners to upgrade to a PS3 rather than a competitor's system. It goes directly against Tretton's two main points about the PS2.
This is baffling to me. It's like watching somebody drive into a wall. Can they honestly not know that the sole reason for the 80gb's higher sales is the BC? It has absolutely nothing to do with the hard drive, yet they're stubbornly parroting that line.
God, I wish that were the case. That would at least make sense, even if I'd still disagree. But whenever this question comes up, I point to Jack Tretton's own words: dropping BC wasn't to save costs.