Sorry, but it's not. There are lots of different ways to play the game, and earning money is not the objective. There is no objective, other than to have fun. Now some people enjoy earning money, but also some enjoy PvP duals, some enjoy piracy, some enjoy trading in a particular style (rares vs normal goods), some enjoy mining, some enjoy exporation.
Having a setback by having your expensive ship blown up is a setback, and may make you unhappy. I'd be suprised if it didn't. I'd argue that the added risk from playing Open makes trading more exciting. Without the fact that it would be a set-back, the excitement isn't nearly so prevelent. The interactions you can have with other players through piracy is interesting (ie. do you run? Do you dump cargo while running? Do you do exactly as they say? How about in the second interdiction where you have 30% hull to start with?).
As I said before though, people enjoy different things, and maybe different things on different days. Some people want to play without the risks of pirates, and PvE private groups or solo mode work great for that. Some people think the potentialy that you will be be pirated adds excitment to every trade run, and hence want to trade in open.