Fujifilm has a lot of vocal supporters for a tradition of adding significant features over a camera's lifecycle. If Nikon is now committing to doing this, that's great news for everyone. Post-launch feature additions are good for the consumer, and if this becomes an expected "feature", we'll all be happy.
As for the opinion that features added later meaning the camera should have been delayed until that feature was complete... I disagree. I'll draw a parallel to general computers, like phones or laptops. Nobody would say "delay Lightroom's launch until they add ML noise reduction", or "delay the iPhone until Siri is available". General computers are expandable platforms, and are defined more via software applications than their hardware.
Cameras have been hardware-only devices for the past 100+ years. If you don't have autofocus sensors, you don't have an autofocus camera. Cameras launched today are much more akin to a general-purpose computer, and are defined as much by their software as by their hardware. For example, the BIF differences between an X-H2S, Z9, A1, R5, and OM1 are down to software. All five platforms have capable hardware; we've all seen each platform track a bird's eye. Things like "stickiness" are software algorithms.
In short, software development is a continuous process. Computers get more useful every year as software gets better. We should not expect cameras to ship "encased in amber", but we should expect manufacturers to continue to support their cameras post-launch!