Funnily enough, losing a ship doesn't really make me feel like I've just wasted hours and hours in that way. The real "investment" isn't the time converted into money through ingame activities, be it generating money through fighting NPC pirates or playing the market, it's the time you spent getting into a position where your characters can effectively make money for you, and that isn't so easily taken away from you again.
I don't really think about a pvp ship much differently than about ammunition. They're an expendable resource, and you probably have a hangar full of replacements just waiting for you to wake up in your cloning pod. It's probably a bit more involved with capital ships and the like, as they are really a group effort so the replacement capacities might belong to your alliance and not you personally, but they're still accounted for before a shot is fired.
In a way, this is really what makes EVE interesting. Losses needing to be replaced doesn't only make EVE battles meaningful on a different level than matches in other games (though I hesitate to say more meaningful...), but it also allows the internet spaceship economy to be very central to the game rather than just some mini-game-like distraction. "Item creation" becomes a question of securing resources and production pipelines and supply lines and whatnot, rather than a one-off effort that precedes the "actual" game.