IIRC from an article that I read, there has been some personal antipathy between one of the OneWeb founders and SpaceX/Elon, that made them avoid SpaceX & go for much more expensive & less flexible "conventional" launch providers.
SpaceX and OneWeb were actually once partners. OneWeb didn't like SpaceX's more ambitious plans (or SpaceX wasn't satisfied with OneWeb's less ambitious plans), so they split.
Re:OneWeb files for bankruptcy
by jagged-chisel on Saturday March 28, 2020 @08:57AM
(#22710855)
I was initially confused because I missed “new” - Iridium’s new constellation is Iridium NEXT.
Iridium used SpaceX very successfully to get their entire new constellation up.