e.g., (totally fictional here!) kieran hebden was listening to the
likes of black dog and two lone swordsmen and influenced by it, but
created his own thing by adding folksy samples and pastoral melodies.
i dont know about all this. i feel like it's almost irrelevant what he was listening to, even though i will talk about it in a second. i feel what you're saying, but i also think that, e.g., i am directly inspired by everything from ovuca to hendrix to art blakey to beethoven to esem to autechre to outkast, and when i am thinking about all these influences when i make a track the end result is that is sounds NOTHING LIKE ANY OF THEM. that's because i dont sample them or try to sound exactly like any one of them in particular. maybe if hebden were sampling black dog, it would be a different story. although i guess maybe the IDM influence comes in more when addressing the structure of the songs, so it's not a very literal connection.
so in summary, i think whether or not folktronica is a subgenre of IDM really depends on different criteria. for example, although maybe not everyone will agree, i find four tet to be very danceable when i see him live, but are there any danceable tracks on apropra't? i dont have the album, nor do i own any Ehlers/Maerz or Auch/Maerz, but i could see that as being a factor in deciding how to categorize this idea of folktronica.
now a side comment on what k.h. actually listens to. maybe i should try asking him, but in his interviews i can never tell if he is serious. he once said that he wanted to push the darker side of jazz like alice coltrane, and another time proclaimed his love for 50 cent. so maybe folktronica is a subgenre of jazz and rap. just kidding. his music obviously doesnt even come close to 50 cent, and the alice coltrane album i have is nothing like it either.
greg