They also represent investment in economic growth that doesn't come from resource extraction or travel or manufacturing.
This is why so many AI proponents always talk about future gains rather than what is happening today. It a lot of what it claimed to be coming doesn't happen then it will all look very silly.
Time will tell and depending on were you sit, either we will be there shortly or it will never happen.
Nope. Every moment that hardware is not ran is wasted money that could have been used to buy something else that's actually productive.
Secondary effects like depreciation make this phenomenom even stronger. You've only got a few years to exploit any given piece of hardware before it's obsoleted by newer, more efficient hardware.
That's why any hardware investment with a high upfront cost operates as close to 24/7 as possible — nuclear power plants, factories. Continuous operation amortizes the costs as well as possible.