Not speaking on behalf of the event team or anything here. The money you got from trading, kills and the influence on the story are reward enough in my opinion. Attend for the sake of fun, not for the sake of getting flooded by rewards.
Separate from Princess, I will note that events that come up from the Event Team (and I presume the Devs/GMs) will have either the reward built into the event (Trading bonus/kill bounty or another form) or post-completion rewards distributed on the forums. This will be clearly noted in the details of the event as posted. In this event the kill bounty and trade profit was clearly posted, with no indications of post-completion rewards. Not every event will have post completion rewards and instead they will be granted through plugin during the event. Likewise, not every event will have rewards given in the moment but given after the event. Very, very rarely will both go hand in hand.
I would also like to note that rewards are determined before the event, not after. I see people complaining yet don't seem to fully grasp that an overwhelming majority victory could've had dire consequences for the opposing factions involved. Going by the ratios given, in a hypothetical Outcast majority win, Atka would've been destroyed and Barcelona forced out of the system in a major Outcast military victory. That didn't happen because each side was, more or less, balanced in one part or the others' participation, so Atka has only sustained damage and neither unlawful side has forced the other out.
Well
It had story consequences
many people spent 40+ hours on the event
And you won't even bother to spend 5 minutes coming up with a forum title they can remember that by, breaking the tradition of every single well attended event since I play the game (none of which announced rewards in advance).
And then on the same token you give out billions worth of stuff and unattainable shields for a 25 minute gank event in Zeta.