I can't ever see a possible collaboration happening between those two. They've already enjoyed success at their highest peak and they want to work with people with major pop relevance. Therefore, working with each other just wouldn't cut it.
Perhaps this would have created major hysteria ten years ago, but certainly not now. J.Lo has smartly jumped on the Iggy Azalea bandwagon and Britney is looking to do the same. Rumours are out there that Britney is pursuing Iggy to work on her ninth studio album. Iggy has already hinted about it on social media. Jennifer was most likely there because she's looking into doing a Vegas residency of her own, since her and Britney are a similar act. How many of you would be here for that?