Uh sry how is it balanced???????? 5 caps and all deff stats they should cost deff amount's.
Given that they cost the same, the caps are balanced BASED on cost.
Essentially, the developers SET cost as the same (other than the battleships), and attempted to have each cap ship provide the same amount of "value". You're assuming that the devs "value" certain ships over others, e.g., that a carrier is ALWAYS better than a colonizer.
Frankly, the worth of cap ships really depends on the fleet you build around them, rather than standing on their own.
On their own, the front line battleships are generally the best, by far. But with a well-built fleet around them, the supports are generally much better ships.
So, they all cost the same, but they provide situational value that differs. I've found that there really are few cut and dry winners, in terms of which cap ship is better.