I've love it if DD produced the Omega 12.0 again, but I don't see that happening. Here's the way that I imagine DD looks at it: Omega 7.0 and 9.0 will always be around because there are a lot of people who bought 16" AR carbines with carbine-length or mid-length gas systems with A-frame front sight posts back in the 2000s, and also a lot of AR makers still producing rifles in that style, so there's a lot of demand for drop-in free-floating rails that can replace the standard ribbed handguards that came on many of those rifles. Whereas the Omega 12.0 can only be marketed to two types of AR owner:
1. Anyone willing to cut down the FSB or replace the gas block on their AR, which won't be a lot of people because it kinda undermines the rail's biggest selling point (i.e., it's supposed to be a drop-in unit that requires no modifications to the host weapon).
2. Anyone with a 20" AR with a rifle length gas system, which is a style of AR that has not been very popular with shooters in the past 20 years compared to carbine ARs with 16" or shorter barrels. When the Omega was introduced (late-2000s), there were still a lot of AR owners who had 20" M16A2 or A4 clones who might have wanted the 12.0 version, but nowadays, it's mostly just retro builders who buy 20" ARs (and they're typically going to just run either ribbed handguards or issue KAC rails, if they're cloners).
For the reasons above: I imagine that DD's BD folks determined that the Omega 12.0 will just always have a limited market appeal compared to the shorter Omegas, and thus won't see any reason to return it back to production.