In the Sound and Vision tour, millions of music lovers who simply attend each and every major concert for a night out fell in love with Bowie's hits and went out and bought his classic albums along with concert programmes and t shirts.
It is impossible to fathom how much money Bowie made during the 90's by licensing his songs to movies. Go over these albums again: each one had several songs used during the credits of great movies, causing movie goers to go out and buy the albums. From David Lynch to Fincher, Bowie's music was in almost every cool movie.
During the NIN tour, hundreds of thousands of young fans became familiar with Bowie's music. He was introduced to a new generation of kids wearing Tool and NIN and Manson t shirts. During the Prodigy tours for Earthling, a new audience again became exposed to Bowie and sales rose. These ravers bought his products along with some E and bottled water.
Commercial missteps? Hardly, hell, the world wide Reality tour alone grossed Bowie almost a billion dollars.