Why are all the Flash Drives made out of Plastic?

A few months ago, I purchased the 32 GB Sandisk Ultra Flash Drive.  I purchased it because of the advertised transfer speeds, the sliding, capless drive and the ability to keep it on a key ring.  The flash drive worked great for a few months.  Since I was able to keep it on my keyring, I always had it accessible.  My love for the drive soon diminished when I took my keys out of my pocket and found that the drives plastic keyring hole had broken.  Not too long after, the drive fell out of my pocket, since it was no longer attached to my keys and I lost the drive with a lot of important data.

I want to know, why does SanDisk not make a flash drive out of a more durable material.  It does not make any sense to own a portable drive with no way of holding it without the possibility of it breaking and getting lost.  Why not create a drive with an aluminum or other break resistant casing?

One word . . .

Money.

Same reason cars are now made out of plastic instead of metal.

There are actually USB sticks made of pure expensive metals. But a lot of sonsumers would prefer plastics since it’s affordable. 

It basically comes down to how it can benefit us. I prefer plastics. 

I have an earlier model SanDisk Cruzer drive, and it is made of metal. It seems most if not all big brand name USB drives are now mostly all plastic, but there are still plenty of OEM or lesser know brands that have metal USB drives.