It does. Once you find them and kill them or take their cargo, they will go into solo/private or change the route. Finding prey becomes harder.
And you know people are actually seeking for me. Traders in a convoy (NPC do that, player fly solo or in wings with other traders and the beacon, usually something under 1mio credits scooping up some cargo).
Traders with friends who actually want to protect their route.
Pirates also look out for bounty hunters, same goes the other way around. Bounty hunting, pirating and assasination/mercenary/hired gun should be just as popular as trading. But nope, you see what people do, they find what brings the most money per hour and stick to it until something changes. Action? Nope.
I've accented the bits I am going to respond to. Don't want to be accused of misquoting you again.
Look at how you refer to these players. As prey. How many people do you honestly think want to spend their leisure time as someone else's prey. Been said before, often, but no-one ever counters this. You play with friends, presumably, how come they (and you) don't sometimes take on the prey role? Is it no fun for you? If that's the case, then you should understand why you have a lack of traders in Open. (Well, it's either that, or Jordan Cobalt keeps stealing your prey.

)
As to players trying to protect their trade route, that normally means protecting it from other traders so it doesn't get traded out. Sure, I get the idea of a trade convoy with heavily armed escorts, battling it out with pirate gangs. It's kind of a scene in a movie, the problem with doing it in ED is that no-one ever dies, so even if the armed escorts destroy the pirates, they just re-spawn and come back, neither side can ever really win it, and it becomes what PvP can only really be in ED, a shoot em up that never ends, that's just like trading, repetitive. Some people want to play that game, some do not.
So, why do people play the game? Perhaps to make lots of money, perhaps to relax. You want to play it as a pirate, that's your choice, but have the decency not to berate others' choices too, you cannot make people want to play with you.
Sure. But this is killing the open play, the multiplayer part of it. Without fresh blood the open mode will bleed out and become empty. Do you like multiplayer games with empty worlds?
As above. Do you seriously, really, expect players who are playing this game for their own enjoyment to be your 'fresh blood'? That's why your Open world is empty, it's nothing to do with FD. If the game was Open only PvP, but otherwise the same, i.e. different ships with different potential load-outs, it would very likely be just as empty.