> Like making food supply work

Producers make what will sell but without any incentives, subsidies or regulation this would be a mess of profit chasing, unsafe practices and fragile supply chains.

In my view, the value of the public sector is in setting the rule of the game for private actors in exactly this kind of way (rules and incentives) instead of the politics of picking winners and losers directly or making direct decisions about what to build where, etc. Rule makers play the meta-game of designing how the game works and they leave agents free to play as they wish.