As a casual player (I work 16 hours a day sometimes), I owned only Sidewinder, Viper, Type-6, Cobra MK III, Vulture, Asp Explorer, and Imperial Clipper
This is all of your post that's needed to make the very accurate conclusion that you are far too inexperienced of a player to know or understand the credit demands of the higher end ships. The rebuy alone for a fitted Conda, not to mention the cutter or the corvette is 50+ million credits.
Now imagine you hit 1 game bug that costs you that rebuy, at the rate in which you think credits should be earned it would take you weeks to just keep up with the rebuys.
I don't think its very fair that you come to the forums and make claims that missions pay out too much when you have never had the requirement to pay over 50 million just for 1 rebuy. Think about that the next time your 2.5 mil rebuy pops up.