"What a greedy fellow," he said with a smile on his face. "Go on. Take as much as you want."
Unfortunately, the metal pillar had a limit on how much lifespan it could use and contain. Because only 1% of its structure was intact, it could only absorb 1,000 years of lifespan before it reached its limit.
After reaching its limit, the pillar didn't stop trying to absorb more lifespan. It wanted to repair itself with the lifespan. But it was lacking the necessary materials for the healing, so the extra lifespan leaked out of it, wasting away.
Seeing this, Loki had to stop indulging the pillar. He stopped infusing it with lifespan. Then he grabbed it and hefted it from the ground.
With a sudden exertion of strength, he lifted the pillar from the ground. Since the ground had become loose, there was nothing holding the pillar down.
