To be fair, most of the phosphate was mined by colonial powers before independence. I think at its peak the trust had $1 billion in investments.

But, yeah the majority of that wealth was extracted by Australia before independence.

Not that any of that excuses the grossly wasteful spending.

But the money's gone, the phosphate's gone, and most of Nauru looks like that crazy bit of Madagascar: https://en.wikipedia.org/wiki/Tsingy_de_Bemaraha_National_Pa...