Just like when Lucas went back and made changes to the original Trilogy: sometimes it's unnecessary and even unwanted to update old things when they were fine just the way they were.
Unnecessary to whom?
That might sound like entitlement, but hey, I’m the consumer Lucas is selling his product to.
Have you considered that perhaps you are, in fact, not the target audience?
But it doesn’t fit the Chart. How can that not bother you?
Presumably because that poster is not quite as obsessed with continuity.
The idea that the TOS ship was also bigger ultimately runs into the TMP version, which was laid out in much more detail at 305 meters
Again, never stated on screen and taking measurements of the sets and the model would make 305m extremely cramped. 380-420 would be better.