Forums like these are echo chambers that reinforce the belief that there are throngs of photographers waiting for the ideal bird-in-flight camera. While there may be many people who enjoy photographing wildlife, most of these people relegate their shooting to vacations &/or workshops. Most are "wildlife photographers" two times a year, but see themselves as serious photographers because they a willing to spend $15,000 on gear, and another $12,000 on trips to photograph fishing bears or gorillas in Rwanda.
Personally, I am a biology teacher and nature photography educator in my region. I shoot twice a week (Saturday & Sunday) and during all of my holiday and summer breaks. There are very few non-professional photographers willing to invest this much of their "non-work" time in the pursuit of nature. Bird in flight photography represents less tha 5% of my time in the field.
While the technology continues to progress, the lack of technology has rarely been a barrier to making unique images of moving wildlife. I've been photographing birds in flight since the Nikon N90 was introduced, and the quality and success rate has increased with every new SLR (film or digital). At this point, the AFc function of the Z cameras are not designed (or not up to spec) with the best autofocusing mirrorless cameras (A9 and R5/R6), but they cost thousands less and will appeal to all of the other photographers that do not belong to this echo chamber.
For those of us here on Steve's forum, we have sought out this place where a wildlife photographer hosts a discussion board. Most of us are likely members of Naturescapes' discussion board, and visit the FM Nature board as well. We are a tiny fraction of the photographic public... a niche market. If you are a bird in flight photographer, and that is all you enjoy, then you are a niche within a niche market, as I want to assure you that your Z6/Z7 mark I can handle just about any "bird on a stick" image. The real photography market consists of parents photographing kids, pets, and vacations. The professional market belongs to portrait, wedding, and journalism.
By our very nature, many wildlife photographers are gear whores... we are in search of gear Nirvana that can do anything. The obsession is so deep that if the camera doesn't think for you, it must be inadequate. The frustration with animal AF that doesn't track a bird's eye, or follow-focus that occasionally drifts to a wingtip instead of head, is enough to make some photographers switch brands.
So while Nikon makes a lot of gear that meets the needs of wildlife and nature photography, they are trying to leverage their brand recognition to appeal to the larger market. Once a vibrant industry, Sports photography is no longer profitable, thus the only real markets left are the average person looking to make a photography a hobby and the few industries where photography continues to be profitable. As such, the priority has been on image quality and accuracy of AF,... not overall AF responsiveness.
Finally, as for marketing... Nikon continues to earn a D or F (teacher talk). They did a fine job creating a buzz about the new cameras but failed again to have real cameras available for people to see, use, and promote. With a deep ambassador program, these photographers should be using the new bodies, cutting videos, and posting images. The absence of these basic promotional pieces suggest that the cameras are not ready for "prime-time" and are still in beta. Nikon would have been better served to have promoted a "coming soon" campaign instead of a "ready to ship in November" campaign. November is less than two weeks away, and I would be super surprised if production models are in the hands of photographers before November becomes December.