Having a huge hit song and then letting countless companies pay to use the hook in their ads is the way to go.
Some people think it is wrong. For instance Frank Zappa successfully prevented advertisers from using his music years after he was dead. Tom Waits said no thanks to an advertiser who then hired a Tom Waits impersonator to act in the ad. Tom sued their butts.
Randy Bachman gets text messages from his agent telling him that an advertiser wants to use “Takin’ Care of Business” every day.
He hardly ever says no.
Here is an interesting article about music copyright and the RIAA.