Webb met a girl of 12 with whom he fell in love, intending to wait until she turned 18 to marry her. But he -- uh, slipped -- when she was 16, got her pregnant and married her ahead of schedule. The marriage killed his songwriting career. I believe it produced "All I Know", written for Art Garfunkel in 1973, which ended up becoming his valedictory song.
His work for the movies has been uninspired, completely without the panache and fine melodies of his early work.
You're right. It's a shame.
*sigh*