From what I learned, they will continue to produce the classic colors of red, black and beige. The problem is, the Disco is highly sought after and sells out pretty quickly on the non-Gucci.com sites (Saks, NM, Harrods, etc.) so inventory is perpetually low. Once they become available online in those stores they sell out again within 24 hours. However, I went directly to Gucci.com and see that they are still available for purchase? Do they not ship to your location?
While I think the new Marmont camera bag is pretty, I don't see how they would think it should be a direct replacement for the Disco. The aesthetics of the two are completely different (one is dressier, more flashy while the other is versatile for all occasions and more understated), they are different sizes, different materials, etc. The Disco is wildly popular, so on a business level it doesn't make sense to force the Marmont as the replacement. Having it in addition to is great, but a replacement? Me thinks not.