These are good times for Libbey, a 125-year-old American glassmaker that nearly went bankrupt four years ago. The company’s shares have risen to almost $20 from below $1, sales of its tableware are at a record high, and its energy-intensive factories saved more than $5 million in 2012 as natural gas prices fell.

Despite all the upbeat news, however, Libbey recently announced it would lay off 200 workers at its plant in Shreveport, La., and move some production to Mexico as it cuts costs and discontinues several products.

Libbey’s decision is just one example of why manufacturing, for all its renewed promise, is likely to fall far short of the claims by industry groups that millions of new factory jobs are about to be created in the United States because of the unlocking of abundant supplies of domestic energy.

“Even though the U.S. is more competitive globally, manufacturing doesn’t give you the kind of direct job creation it did in years past,” said Joseph G. Carson, director of global economic research at AllianceBernstein, a Wall Street investment firm. “At the end of the day you still want a strong manufacturing base, but there aren’t as many people on the factory floor.”