If they were done or so close to being done, why dont they just release what they had out for free?
Because a) it may have been "nearly" finished, but that doesn't mean the game was playable. and b) that would prevent LucasArts from ever resuming work on the game.
Yes, I know it's extremely unlikey, but they will want to keep that option available. And 3) it's possibly damaging to the Sam & Max brand if there's an unfinished, buggy, game floating around in public and I don;t thing Steve Purcell, LucasArts or even all the let-go workers from the Sam & Max team would want their unfinished, unoptimised, unworking
code floating around the internet.