I think it's because guys are gaining too much weight. Even when you put on extra muscle, your joints and ligaments aren't any stronger. Guys joints and ligaments were born to support the explosive movements of players at their natural weight, not their natural weight+20 or 30 pounds.
Because he broke his hand? It's just a freak accident dude. Injury prone is when you have, like, recurring hammy issues or sprains or whatever.
I agree. I wonder how LeBron is playing his 9th or 10th season and still no signs of even minor injuries. You need a hell of a lot muscles and strong ligaments to move such mass around so fast. Or DWill/DRose against Parker/Nash.