I wonder about actual effectiveness of spending on railroads vs AI... Even if railroads were somewhat waste, did the investment spread much wider? At least geographically it must have as there were workers that moved around and needed services. That is it was mostly spend in economy. Thus had actual change to trickle down.

Where as AI, who actually gets the investment? Nvidia? TMSC? Are people who are employed some that would have anyway been employed? Do they actually spend much more? Any Nvidia profits likely go just back to the market propping it up even higher.

How much efficiency from use of LLMs have actually increased proctiveness?