I think its not fair to put the Elbphilharmonie in the same category.
The original plan looked very different from what was later realized. Which was a significant driver of the cost.
Just for fun, lets compare it to the Sydney opera house:
Elbphilharmonie, original projected cost: 186 Mio EUR
Elbphilharmonie, final cost: 866 Mio EUR
So in the end, 4.65x the projected cost and 7 years late.
Sydney Opera house, original projected cost (inflation adjusted cost in parens): 7 Mio AUD (70 Mio EUR)
Sydney Opera house, final cost: 102 Mio AUD (632 Mio EUR)
So in the end: 9-14x the projected cost and 10 years late (depending on if you compare based on the inflation adjusted costs).
Therefore, in comparison, not that dissimilar.
The original plan looked very different from what was later realized. Which was a significant driver of the cost.
Just for fun, lets compare it to the Sydney opera house:
Elbphilharmonie, original projected cost: 186 Mio EUR
Elbphilharmonie, final cost: 866 Mio EUR
So in the end, 4.65x the projected cost and 7 years late.
Sydney Opera house, original projected cost (inflation adjusted cost in parens): 7 Mio AUD (70 Mio EUR)
Sydney Opera house, final cost: 102 Mio AUD (632 Mio EUR)
So in the end: 9-14x the projected cost and 10 years late (depending on if you compare based on the inflation adjusted costs).
Therefore, in comparison, not that dissimilar.