The prez is supposed to implement, administer, enforce the laws or acts of Congress, and he hires people to do that, that are organized according to their task.
Because Congress was creating many environmental laws/regs, such as NEPA, CAA, CWA, etc, they created EPA to do that. The Occupational Safety and Health Act needs a Occupational Safety and Health Administration. The Federal Lands and Policy Management Act needs the BLM. A tax code, created by Congress, needs IRS to enforce it. The Endangered Species Act needs USFWS.
Sometimes they re-organize, such as in 2003, when they created DHS, or at the end of WW2 with CIA.
You can do away with EPA, but somebody still has to fulfill those duties; which are defined by acts of Congress and subsequent Judicial decisions.
I still fail to see where even Congress is authorized for those that you list....Must be my copy