Why does my Lactaid last almost indefinitely?

Factual Questions
1

Many years ago, I switched to lactose-reduced milk, most often Lactaid. I’ve noticed that refrigerated Lactaid lasts months in the refrigerator. I can’t remember one occasion on which my Lactaid spoiled. Which has resulted in my forgetting that regular milk does spoil, resulting in stinkyness when I’ve bought some for guests.

Anyway, my question is why does Lactaid (seemingly) never spoil?

2

Lactose turns to lactic acid and accelerates the spoiling of the milk. Also, I believe lactose-free milk is ultra-pasteurized, which also helps prevent spoilage.