I was using the term "endgame" to show that those ships are supposed to be the biggest, baddest motherduckers available to players, and juxtaposed that term with the reality of the situation.
You're limiting yourself to your own POV. "The corvette is not a ship to do X with" is your own opinion. I got the game on the premise of being able to "blaze my own trail" in a "multiplayer space game with MMO features". I'm not making anything up, merely quoting what was on the steam page at the time. The reality is far from that.
You imagined yourself bringing your hypothetical corvette to a CZ, but the corvette is far from the best option to bring in a CZ because it costs a buttload to rebuy, it's slow as sin (can't escape when masslocked by several other corvettes and cutters) and the profits to be made in CZs are slim at best unless you stack massacre missions. Add that to the fact that AI will prioritize players over NPCs (especially when using a big ship) and you got a recipe for catastrophe unless you go there with a wingmate. If you don't it would be a case of making 5M, losing 50 potentially and so on. You're better off bringing the smaller, faster, more agile, just as tanky and cheaper to rebuy FDL; or the tankier and faster "LOL can't be masslocked" Imperial Cutter.
My point is: big ships are almost useless and the game severely limits what you can do with them through various means but mainly because MONEY.
I also did not grind, merely played for about a year at the leisurely pace varying between 10 to 100M per week thanks to bounty farming, high value piracy, smuggling and mission stacking.