He was basically a complete loser during his lifetime is my understanding.
I believe part of his clothing was because he was totally broke. A broke surrealist eccentric alcoholic who's music was largely rejected for being overly simplistic during his lifetime is the picture I get of him.
Idk about the rest, but Satie was like 30+ years older than Poulenc, and died a few years after Poulenc's first composition.
I don't know if you can characterize them as friends. Satie's music definitely influenced Poulenc's, a lot.
Satie was broke as hell too, that part is true. Idk if being broke makes you a loser, but it might explain his choice of clothes.
I don't think of him as a "complete loser" at all, not even close. Do losers have Picasso create the sets for their ballet composition (Parade)? How many "losers" have a homage of them painted by Salvador Dali? His friends included Debusy, Ravel, Poulenc, Man Ray, and the list goes on. Loser? He was a creative icon amongst creative icons.
Don't confuse eccentricity for being "a complete loser".
>In 1911, when he was in his mid-forties, Satie came to the notice of the musical public in general. That January Maurice Ravel played some early Satie works at a concert by the Société musicale indépendante, a forward-looking group set up by Ravel and others as a rival to the conservative Société nationale de musique.[44][n 8] Satie was suddenly seen as "the precursor and apostle of the musical revolution now taking place";[46] he became a focus for young composers. Debussy, having orchestrated the first and third Gymnopédies, conducted them in concert. The publisher Demets asked for new works from Satie, who was finally able to give up his cabaret work and devote himself to composition. Works such as the cycle Sports et divertissements (1914) were published in de luxe editions. The press began to write about Satie's music, and a leading pianist, Ricardo Viñes, took him up, giving celebrated first performances of some Satie pieces.
Doesn't sound like a "complete loser" to me.
I can tell you as a musician, that sometimes the music comes before all else, including feeding and clothing yourself, and even basic hygeine. It's an addiction like no other and if you really give your life to it, then nothing else really matters. That isn't being "a complete loser".