Do away with, or revise, the National Minimum Drinking Age Act (1984) to establish a national minimum drinking age of 18

The National Minimum Drinking Age Act of 1984 required "all States to raise their minimum drinking age to 21 within 2 years or lose a portion of their Federal-aid highway funds."
It is not the government that should be doing things of this nature, like trying to control the drinking age. That is more of a family matter, as it should be up to the parents of teens to educate them on responsible drinking, not schools and not the government.
There would be more jobs available to those under 21 if the drinking age were set back to 18. 18 year olds could be bartenders, or work in the manufacture of alcohol, which is a really big business in the US. If 18 year olds were allowed in this industry, there would be more people in the workforce, and give the economy a boost.