How did The Who's "Teenage Wasteland" also become known as "Baba O'Riley"?

"Baba O'Riley" is sometimes incorrectly referred to as "Teenage Wasteland", which is, however, the title of Townshend's original demo, as included in The Lifehouse Chronicles box set. "Baba O'Riley" is informally known by its chorus line "Teenage Wasteland".
https://en.wikipedia.org/wiki/Who%27s_Next

"Baba O'Riley" (often mislabeled as Teenage Wasteland) is a song written by Pete Townshend for his Lifehouse project, a rock opera that was to be the follow-up to The Who's 1969 opera, Tommy.

answers.com/Baba%20O'Riley webpage no longer exists

The song is known as Baba O'Riley. Nobody remembers that correct title, so they mistakenly refer to it by it's most memorable lyrics..."Teenage Wasteland." The name Baba O'Riley does not appear in the lyrics.

The band members of The Who were putting character traits into a computer/synthesizer to see how the computer would transform the information into musical notes. When they put in the information for Meher Baba they got the intro musical line in the beginning of the song....then put the rest of the song together.

What I've been told is that the group asked their guru Baba O'Riley what he thought of the Vietnam War, he replied that it was a "teenage wasteland".

Thus the song is really about the Vietnam War, not drugs as most people assume.

The title of the song is derived from this combination of the song's philosophical and musical influences: Meher Baba and Terry Riley. Parts of the rock-opera Tommy were inspired by Townshend's study of Meher Baba, to whom the album was dedicated.

Terry Riley is a composer and musician asscicated with the Minimalist school. In the 1960s he gave famous "all night concerts" during which Riley performed mostly improvised music from evening until sunrise, using an old organ harmonium ("with a vacuum cleaner motor blower blowing into the ballasts") and tape-delayed saxophone. When he finally wanted a break, after hours of playing, he played back looped saxophone fragments recorded throughout the evening.

I got all of the above from googling baba o'riley. Then I went to Wikipedia and looked up Meher Baba and Terry O'Riley. What you see is copied & pasted from Wikipedia. Don't be afraid to use your search engine...it is your friend ;)