It seems like AMD isn't planning on releasing a Ryzen 7 2800X because their line-up seems to be sufficient for now. This however doesn't mean that there's no Ryzen 7 2800X at all. The existence of the Ryzen 7 2800X has been rumored by Jim Anderson, who talked with DSOgaming.
“We felt like, with the 2700X and 2700 at the performance and price points, we had that space covered. We just felt that with those two SKUs we had it sufficiently covered where we wanted to position the product.”
“That doesn’t preclude a 2800X someday, right, maybe. But for now we believe those two SKUs cover the space well.”
While we were not able to test the 2700/2700X ourselves, it seems like both chips occupy top spots in terms of price and performance. Their strategy could be influenced by the upcoming release of intel's new eight-core processor for socket 1151, this would allow them to take advantage of the situation and get part of the chip's sales.
Currently AMD's line-up consists of 6 chips (2 Ryzen 7's, 2 Ryzen 5's (6cores) and 2 APUs (4cores)). We'll see what the future holds.. Stay tuned!