So you replaced the passenger side upper ball joint last year, and now the driver's side upper ball joint failed? That could be catastrophic.
Are you able to post a picture of the failed ball joint? I'm picturing a ball joint that got so loose that the stud separated. Did you notice any wandering when driving?
Are annual vehicle inspections required in your state?

 

Thought the ball joint was steel regardless of whether the control arm was steel or aluminum? I have the option of steel or aluminum at the parts store as they have both.

 

No wandering when driving, everything seemed fine. No annual inspections here. Pics show the pressed in top of ball joint pulled out of the control arm. Looks like it has some type of glue they use when pressed in on these :

 

damn it dude. never saw that before unless it was a wreck. what brand was that?

 

I'm guessing the cup might be steel, but it's pressed into aluminum... which just ain't as strong. Again, just my guess. That's not somewhere I'd want to save weight. Safety is paramount.

 

Control arm looks OK to me. Are you going to replace the ball joint yourself? I think driver's side is easier because you don't need to remove anything from the engine compartment. I had to remove the plastic wheel well cover to get clearance for the press, but that was no problem.
I'm trying to picture the fitting you would use on the ball joint press. Since the ball joint stud is gone, I guess you would just use the bare tool on the bottom.
Now I know what the inside of a ball joint looks like.

 

Not sure on the brand, it's an aluminum one though, which is what the truck used originally apparently.

I looked at the aluminum control arm and the steel today at the parts store, same price, ball joints looked the same, aluminum is much lighter and went with it since the passenger side I changed last year is aluminum and thought one steel and one aluminum might act weird with the suspension as the aluminum ones have more flex. If I was buying a pair I'd just go with the steel.

From what I've read you can't change just the ball joint on an aluminum one and they don't sell just the ball joint in my city either, only the control arm with ball joint pressed in.

I went with the Pro Series OE+ Aluminum Control Arm ($94.99 Canadian), same as I put on the other side, it seems to be a rebranded Dormann made by Mas Industries (Made in China unfortunately, hard to get away from that nowadays) :

 

Don't know about your rebrand, but Dorman is pure unadulterated crap. I wouldn't trust their parts to last long and wouldn't use one where it could be dangerous if it fails.

 

I'd recommend not getting the same brand as the one that failed. I've never seen a ball joint separate suddenly like that. The ball end of the stud looks like it has no grease at all.

 

May go back and get the steel one then, its under the same Proseries OE+ brand but manufacturer # shows it as a rebranded Moog CB7424. Do you think there would be issues with having one side steel and one aluminum? I'm guessing the Moog would be a more quality part over the Dorman?