with all due respect, the movie was started in Kickstarter back in 2012, filmed in 2013, but "The film debuted at the American Documentary Film Festival in Palm Springs, CA, on April 3, 2017. " Imagine the shock when I saw Go Seigen in the film.
What took them so long to put it out?
I would guess they ran into some hiccups in post production and didnāt want to release until they were satisfied with the end product (from what Iāve seen, it was worth it)
Not a big company behind it but simply Go lovers. Plus, considering the quality of the film, Iād think they are perfectionists 
A list of all streamers who put up ads:
I donāt know, maybe hiccups as in ārunning out of moneyā. LOL
Not uncommon with kick starters