I think the main issue is that ships are too cheap.
Nah.
More expensive ships just means people grind more smuggling to get the fleet they want, and are that much more likely to ragequit on losing a fight.
It would make salvaging ships to sell more viable though, assuming the ships are made expensive through an increase in base price. Are bounty prices also calculated based on the value of the enemy ships?
It is odd that the outstanding benefit of combat isn't credits ,loot, or taking out competitors, but XP gain. Trading is far easier if you have the first 2 science skills, Bulk transport and a couple other industry skills whose names I forget ATM and the commission stipend scales with your level. It likely stems from the all-or-nothing nature of fights in this game. If trading wasn't so powerful getting back on your feet after a fleet wipe would be even more of a slog, and almost every hostile encounter is either a victory, a full fleetwipe, or a pursuit that only your frigates can escape unless you burn a story point. You'd think pirates would try extortion occasionally, much more profitable to steal a full cargo ship than to scavenge its exploded hulk after all, or that you could capture ships and crews rather than destroying them all.