I'm not sure if you mean mine or theirs. Theirs is definitely bad. Mine was not an analysis, just pointing out how bad theirs is. The original investment was in 2008. $1 billion invested in an S&P500 ETF would have returned the original investment plus a couple billion more. Even still where they are at in 15 year does not work out to a really high interest rate. It's still sub 4%.
As I posted upthread, the 2022 nominal return was more like 12%, 6-7% when inflation adjusted. Assuming parking demand doesn't collapse, which seems unlikely given ongoing gentrification and decreasing transit usage, that sub-4% rate is about to go up by quite a bit.
This investment pays dividends. The original investment has already been paid back in cash, plus $500 million.
There is an opportunity cost to money.