> Private companies would go down if they do projects with negative ROI.

private companies indeed go bankrupt all the time.

> Governments [don't care]

many governments care.

see the table on the second page https://www.oecd-ilibrary.org/cost-benefit-analysis-of-inves...

> Governments don't know what has positive ROI

and? no one knows with absolute certainty.

we should prefer market based solutions when they work, and we should work on making markets applicable to as many problems as possible, and we should definitely keep an eye on the usual regulatory capture problems (revolving door, incumbents lobbying to keep competition out, etc..)

markets work when the playing field is clear and equal. (for example global trade works if the seas are clear of pirates, and when there are mechanisms to keep rate of counterfeiting low enough to have trust between consumers and producers.)

https://marginalrevolution.com/marginalrevolution/2020/01/wh...