That is nothing but an ideological statement without any evidence, one that is being disproven as we speak.

Free market economics haven't worked out great for the vast majority of people.

Free market economics is working great for the vast majority of people. Median living standards in capitalism countries are higher than ever. Regardless of ideology the data is quite clear on this point.

Go ahead, plan my Christmas Eve. What time I wake up, what time I leave the house, which routes I take, what things I buy. Assign the kWhs of electricity and liters of water and fuel that I'll use up, plan ingredients for my meals of the day.

The belief that a central "digital planning engine" could plan the lives of an entire society is an incredibly naive idea from early cybernetics. This doesn't work even in small thought experiments because of information limits. No central system can access all the local knowledge and constantly changing circumstances.