not sure that we cannot allocate capital, the previous generation harvested most of the low hanging fruits, it can be argued that most modern progress needs more and more energy, and we are on a path of diminishing returns.

See the various options under :

https://en.wikipedia.org/wiki/Secular_stagnation

and

https://en.wikipedia.org/wiki/Energy_returned_on_energy_inve...

the world is not infinite, and economic growth can not be infinite.

I have no proof if we are effectivelly at "the limits to growth" or not. It sure starts to feel like it.