The freeport 7 exploding scene was done in a specially made system by the game developers. As for freeport 3 and the other one...guess they got blown up by crosairs or sumthing cause the Zoners don let them trade cardamine onboard ..

'Freelancer 1-1, I am scanning ur cargo bay for contraband'

Even if FP7 was completey destroyed, the trade lanes leading up to it would be there.

Sorta off the subject but first off, Ourcasts sell Cardamine, not Corsairs-or do the Corsairs also sell it, secondly the Zoners let the Outcasts come to their bases with Cardamine and everything, it's just not sold there, unless they hold some grudge against the Corsairs I'd see no reason they'd not let them do the same. Third FP3 and FP8 were probably both abandoned and taken over by another company, like the BMM and IMG did on FP4. I think it was BMM anyway...