The Department of Energy manages the nation's power supplies,
The power companies are quite capable of that.
Department of Commerce collects taxes,
I thought this was the responsibility of the Treasury Department.
the Interior governs our damn national parks and the immense stretches of government-owned land along with all our environmental efforts
It's worth noting that the federal government owns 30% of all US territory. Should it?
The Department of Education mandates school curriculum and is perhaps the only way social mobility even exists, let alone educated poor (free lunches etc.),
The DoE oversees a few school services that should be provided by states or other organizations. It also regulates, often detrimentally, state education as if the states or school districts are unable to do so themselves.
weather forecasting would be impossible without NOAA, and neither would our current understanding of climate change, without NIST our clocks wouldn't run on time and our industry would not have any baseline standards, and without the USGS, well, we'd have no idea what our natural resources look like--or our flood risk, earthquake data, and so on.
Private companies and other organizations do many similar things - satellite imagery, weather forecasting, standardization, risk assessment. Why not also do these?
Without government spending a great many things that people take for granted would disappear and the world would become a much more unpleasant place.
How do we get bread baked and distributed to stores? What federal agency oversees the care of abandoned pets? Services we consider unthinkable without the government are services that have been provided elsewhere, separate from a massive institution that claims authority to rule us under threat of violence.