Beyonce gave Stargate their breakthrough as the top new producers when she gave them their first smash with Irreplaceable. It's smart of her to work with them again; out of the popular hitmaker producers, they're the best.
Why didn't they give "Diamonds" to Beyonce though, since it's such a smash?
Would Beyonce be able to make "Diamonds" go #1 in almost 20 countries?
How do you know they didn't offer it to Beyoncé first? Maybe she rejected it because she felt that she had better material. Maybe Sia had many songs and Diamonds was one of them and Beyoncé just didn't like it. Maybe there were better songs, you'll never know. But it doesn't matter anyway, I don't even know what you're trying to reach. If you're here to "shade" Beyoncé just leave because you're doing a horrible job.