“Coal is not coming back,” said Joshua D. Rhodes, a research fellow at the Energy Institute at the University of Texas at Austin. “Further subsidies right now will only prevent workers from being retrained or building careers elsewhere — which will make things even more painful when the bottom finally does drop out.”

In the latest such move, Mr. Trump asked Energy Secretary Rick Perry on June 1 to “prepare immediate steps” to halt the closing of unprofitable coal and nuclear plants. While administration officials are still debating how they might do so, any plan to rescue these power plants would probably entail dramatic government intervention in America’s energy markets and come at the expense of newer, cheaper power sources like natural gas or wind.

A decade ago, coal provided nearly half of America’s electricity. That share has since plummeted to less than one-third, as coal has been driven out of the market by stricter pollution regulations and a glut of cheap natural gas from hydraulic fracturing. Wind and solar power, while starting from a small base, have grown at double-digit rates each year as the technology improves and costs drop.

The jobs have followed: The number of American coal miners has fallen from more than 80,000 in 2008 to about 53,000 today. The solar industry alone now employs twice as many people as the coal industry does. Solar installers, wind technicians and oil and gas drill operators are all expected to be among the fastest-growing occupations over the next decade, according to the Bureau of Labor Statistics.

“Ten years ago, the joke among industry players was that renewables were the energy source of the future and always would be,” said Andy Karsner, a former assistant secretary of energy in the George W. Bush administration. “Problem is, that future has arrived, and coal is now the energy source of the past and always will be.”

Manufacturing jobs have fared better under Mr. Trump but remain at a historic low as a share of the economy. Fewer than 9 percent of American jobs today are in factories. While primary metals manufacturers in the United States — including steel and aluminum mills — have added 11,000 jobs since Mr. Trump took office, according to the Labor Department, total employment in the industry remains under 400,000 jobs nationwide, down from nearly 700,000 jobs 15 years ago.