They got rid of Seska and Cullah first.
Season one and two had a greater budget that was dedicated to supporting characters.
In season three, Berman (And Taylor? She was really against story arcs and continuity. She stole Chakotay's baby.) sacrificed those two, or whoever would replace them as Voyager continued to move through yet more foreign space, in favour of increasing their spfx budget for space battles and explosions.
If they wanted to keep Jennifer, all they need to do was bring the spfx budget back down to season 2 levels.
I know, I'm a riot.