There's a reason most ultralight's aren't offered in varmint calibers and most 22-250's are still a 1-14" twist. I realize there are a few consumers who'd like a quicker twist but until the majority want it different, it'll remain this way.
The majority probably just doesn't know the difference and also wouldn't know if they suddenly started selling them w/ a faster twist! There really isn't a downside that I can think of.