'Frequency' of these rewards being given out - We are holding a crafter olympics right now as part of an in-game storyline. You can read about it in its thread in player ran events. That is why there has been an above average number of rewards handed out in sequence (there are 3ish more events to go).
UoH have held events more than weekly for a year, literally. There has been maybe 25 rewards handed out for player ran events in the shards over two year history. The idea that these rewards are being handed out frequently in the big picture is a failure to do math.
Crafter Events - There are no automated crafter events. These must be made by players. 'If' there were automated crafter events that awarded silver or some other prize to players, would anyone be saying anything? or this because they are not automated they should not have any prizes? 12? crafter prizes in a 2 year history of a shard should not be cause for panic, only concern there is not enough prizes compared to pvp events (1000ish? pvp trophys vs 12 crafter event prizes?). And yes these are not the first crafter events

Rewards - Most events we personally supply the reward, to say that every event we run is staff delivered prizes is insulting and again, off base. Either it being silver/gold/rares etc. Items on bosses, treasure maps to be spawned. This comes from our pocket. When a Gm deems it fit and we have requested, they grant a prize to the winner or participants, which is incredibly rare vs the number of events. We could go two months of solid events and never get an admin assisted reward. Many events we run staff are not informed, there is no system message and there is no special prize.
As for all discussion of 'We wouldn't get that if we asked'. If If If If - try holding a bunch of well organized events and asking. I went to 4 or 5 events ran by players, prizes provided by staff before I ran my first event. I think my first was Kylock's pvp tournament. It had a pretty cool angel statue prize. Staff have always shown more than a willingness to help players trying to do something positive for the in game community.
Running the museum and holding events is incredibly expensive, it also takes up a lot of my time and will power. I don't hold these events so that I can win them. I have never walked away with a trophy or prize from any of these events. I hold these events so that players who arent 'super power gamers' have something fun to do outside of their normal game play. The fact that a player who plays a tinkerer walked away with a tinkerer prize should not bother you.
It really should not.
A player's motivation for taking part in a player ran event is not a legitimate point for or against admin prizes to player ran events. Players come to a player ran event for a chance at a prize? is this something new? The 'size' of the prize should really not reflect the number of participants. That is a poor way to gauge the failure/success of any event. We have held events with 50+ players and I would say they were no more successful than events with 5. I have much experience with this.
We do everything we can to let all players know the events are taking place, you know they are taking place. Instead of participating in these (once in a shards lifetime crafter olympic FLINT MICHIGAN MEGABOWL) events for a chance at a prize you decide to grief them and try to murder players. This is an obvious extension of that in game attitude on the forums. Instead of trying to derail players trying to do something positive in game, you should get out there and host some events and try to improve other players gaming experience, instead of just your own. Earn those town add ons you have and most obviously deserve.