I think it's more to do with company/dev size. The bigger companies take longer to migrate than smaller startups and lone devs. I'm in a small startup and it wa

I think it's more to do with company/dev size. The bigger companies take longer to migrate than smaller startups and lone devs. I'm in a small startup and it was trivial for me to change over to Swift as I'm the only iOS dev. Facebooks SDK is still being written in Objective-C so I guess it's simply harder for them to jump over because it's a much bigger project.