Overall, this is a bad situation Star Trek 4 finds itself in, and if Paramount can’t entice Pine to re-negotiate, then there’s no need for the movie even being made.
Say what you will about Star Trek Generations, but at least he we saw him go out as a hero.
The other option is that Star Trek 4 is rewritten so that James Kirk isn’t in the story at all, which would be an even bigger mistake.
The original Star Trek characters form one of the most well known casts in all of pop culture, but without Kirk sitting in the captain’s chair, it just wouldn’t feel like a proper adventure starring the Original Series era characters.