You are also assuming the thief would have any idea its 7 years old. Lot of laptops get snatched from passenger seat of the car or in a shop - while its in a bag....
7 Year old laptops are far from worthless and besides you should see how some of the forum members react to +15 year old consoles
You want a funny theft story? I saw a CL post for an Apple laptop, no battery no power supply someone wanted $1000. I looked, it is a Powerbook Duo 280c (released early 1990's) with a rather distinctive sticker on top. Called my friend, he said his was stolen, he checked CL, yep it was his, he called police about the listing. Seller got busted with the laptop and a bunch of other stolen goods. The laptop did not have password protection but no one would pay $1000 for a (then) 15 year old laptop with no battery or power supply. So yeah people would steal even very old laptop because they are idiot and thinks all laptop are worth big money. I should look for an early laptop (like 386's or 486's) and leave it in my unlocked car. Better yet, one that is wired with a bit of C4 inside so if the thief tries to power it on, boom.
It couldn't be unlocked with the manfacturer's master unlock code? Some codes of some drives have been leaked onto the Internet, and tools like MHDD can be used to unlock the disk.
Most laptops set both the user and master password - the theory being, you can give the user the user password so they can use the laptop and the admins have the master one to reset it.