I think what really went on is they got paid to work with Simon as 'work for hire' - which means any music that transpired was Simon's to do whatever he wished.
This is one of the greatest albums ever recorded. Start to finish. Masterpiece.
And talk about leading the way in pop! Reggae, Latin Boogaloo, Django-style gypsy jazz, etc. right next to Bach-inspired acoustic compositions. And the lyrics! As Robert Christgau wrote way back in '72: "This is a professional tour of Manhattan for youth culture grads, complete with Bella Abzug, hard rain, and people who steal your chow fong."
"Peace Like a River" may be the absolute pinnacle of his catalog.
There's a longer account, where the label head pretty much begs them to come and play, as a favor.
They fart around for a day and call him to tell him they won't be back, and he keeps begging them...
The second day, they show Simon "Myth" and he likes it.
Of course, we'll never know, but if you can't picture David Hidalgo singing that melody, you've not familiar enough w/Los Lobos' work to weigh in, IMHO.
I'll put Paul Simon up there with Lennon/McCartney and Dylan. His output was strong through the 80s. Maybe not now. McCartney's writing since Wings ended hasn't done anything for me. Dylan has been hit or miss in the 80s and later.
Justin Bieber is said to be worth 100 million. I don't think how much a musician is worth is an indicator of talent.