Yeah, MIM assembly-line guitars can certainly depreciate. Even a brand new Made-in-USA Fender Strat, used, will sell for less than it cost new. They don't start gaining value the minute you walk out the door with them, because they're not one-of-a-kind or collectible. Thousands and thousands of them (Even Made-in-USA) roll off the factory line monthly. It would be pretty tough to convince anybody that anything but a true collectible (50's, 60's... some people are starting to value 70's including the 3-bolt versions) has gained value from the date of its original purchase. A MIM jobbie even less likely (near to impossible) to do anything BUT depreciate.
The only way these things gain value is when they're sought-after for some reason, naturally. Let's say for some reason, researchers identified that a... I dunno... 1992 USA P-bass had a slight variation in its manufacturing compared to other years. Then players for whatever reason started recognizing an improved tone or playability. And perhaps it came in a colour only available in 92/93 or something... (I'm just talking in cloudland here). It would start gaining a reputation and would therefore start becoming collectible and would therefore begin to appreciate. My Guild acoustic is MAYBE becoming a bit collectible because they got purchased by Fender and the manufacturing process changed from when I got my guitar.
This bass ain't that.
Now, I don't mean to contradict you and make you feel bad or anything, but even $500-600 isn't too much money for someone to spend on their first instrument. I think people should save their money for an extra month and get something with a bit of quality to it, as their first, whenever possible. If the extra $150-200 represents a LOT more than a month, then eventually you're just going to have to purchase within your resources, which is what this kid seems to have done. Point being, spending money on a first instrument isn't necessarily a bad thing-- It inspires you to play when you're not fighting with the gear. I might have become a skateboarder if I had realized as a kid that my "Consumer's Distributing" skateboard would never allow me to do ollies or roll along properly (it was heavy and the bearings were no good!). Years later, I tried out a "real" skateboard and went, "OH! It wasn't just me!" Of course, now I'm an old fart.
Greg