Not quite accurate - they made Iggys first solo album, The Idiot, during this period, which is a fantastic album but a) basically just a Bowie album with Iggy doing all of the singing b) had no big hits. Bowie basically wrote that album and his own (Low) at the same time, but then decided touring with Iggy would be more fun, so he didn’t do a tour for Low and just started gigging with Iggy as his keyboard player.

During those live shows they came up with a bunch of ideas that they then whipped into Iggy’s second album, Lust for Life, with only a little only a week of studio time, and that second album became the biggest hit of Iggy’s career (because it turns out the computerized alien funk that Bowie made in a studio didn’t work great for Iggy, but putting him in front of a kickass rock band and just letting them burn the house down worked great).