Because Star Trek has become too confusing and over saturated with too many timelines and too much fragmentation, both in its world building and in a production sense. The movie series in particular seems to be ‘coasting’ and stalling, showing that perhaps it is in need of reinvigorating and energizing once more. A franchise reset, which can still use the JJ-verse crew in a similar way as to how Star Trek: Generations mixed crews, would be the perfect solution to soft reboot the franchise ready for a new 25th century continuation series which goes back to the basics of what Star Trek was in the 1990’s. If Strange New Worlds can revisit 60’s Trek, I do not see why a true continuation of 90’s Trek cannot be fair game for source material and inspiration for a new streaming show or movie series.
Whilst this reset movie is being made, they can fire out a Prodigy movie to help reintroduce a new audience to the later 24th/early 25th century characters and settings such as Janeway.