Billionaire financier and sometime politician Michael Bloomberg has announced a $1.8 billion gift to his alma mater, Johns Hopkins, to use for financial aid. This is splendid, but it got me thinking.

Bloomberg’s net worth is about $51 billion, making him the eighth-richest person in the U.S. and the 11th richest in the world. The subway system in New York, where Bloomberg was mayor for 12 years beginning in 2001, is in a state of advanced collapse.

Bloomberg was big on reducing car traffic in Manhattan. He was not big on finding the revenue to fix the subways, which is key to persuading people to give up cars. The cost of bringing the New York subway into the 20th century, never mind the 21st, is estimated at $37 billion.

Bingo! Bloomberg could write a check, and would be forever remembered as the man who put his money where his mouth was. They would erect statues to him. He would enhance his chances as a presidential candidate in 2020. And he’d still have 14 billion dollars!

Maybe he’d even be a role model for other mega-billionaires. Of course, this remedy is a second-best. The first best would be a serious system of progressive taxation so that public facilities would have adequate funding without moguls writing checks. (Ditto financial aid for college students.)

Still, as a second-best, the renamed New York Bloomberg Metro would be pretty cool. Whaddya say, Mike?