Except that it didn't.
Before Spotify, "podcasting" meant "open medium based on web standards". Spotify embraced/extended/extinguished it to the point that even technical people happily call shows distributed on closed platforms like Spotify and YouTube "podcasts".
Since freeing the word "podcasting" from its open, standards-based chains, Spotify now claims to be the largest podcast listening platform with 25% of U.S. listeners. As a closed platform, there's no way to independently verify whether Spotify is cooking their metrics books.