Secondly, the scale of investment in AI isn't so that people can use it to generate a powerpoint or a one off python script. The scale of investment is to achieve "superintelligence" (whatever that means). That's the only reason why you would cover a huge percent of the country in datacenters.
The proof that significant value has been provided would be value being passed on to the consumer. For example if AI replaces lawyers you would expect a drop in the cost of legal fees (despite the harm that it also causes to people losing their jobs). Nothing like that has happened yet.