While it is necessary to get to the final stage of the tree for everyone to get a reward, it is not required for some to get a reward. The point thresholds are scaled such that there is a much smaller gap between the earlier levels than the later levels. Also, keep in mind that your chance of getting a reward is directly related to the value of the BODs you give to the elf. What this means is if you've turned in 5,000 points worth of BODs you are going to have a much better chance than someone who has turned in merely 100 points. Also keep in mind that someone is only eligible for one reward each time the festival is run, and that the point thresholds relate to a percentage of the participants.
For those on smaller shards you have a few strategies...
1. Have someone like Shandara from GLs who is a BOD power-player and progresses the tree to maximum growth almost entirely on their own, resulting in everyone from a single point turnin player to a multi-thousand point turnin player receiving a reward.
2. If you don't have a Shandara you can build up a supply of BODs to turn in to a single elf in which case your score is more than likely going to put you in the upper tier of those who turned in BODs resulting in much greater chances of getting a reward. Remember rewards are awarded to a percentage of participants based on the growth state of the tree, and each participant can only get one reward per tree - so the more you individually turnin, the better your chances.
3. Coordinate & plan with your shard community to build a substantial enough stockpile that betters the likelihood of pushing the tree to the highest growth level. Rally your guild, cajole your friends. Have a BOD craft-a-thon. Then, when the time is right, rush the tree with all those glorious points. Should you be successful in your mission, you'll have a fully grown tree which will distribute a reward to everyone who participates. Once the tree reaches full growth you can continue to participate, so break out all the alts and get enough gifts for as many characters you have to turn in a BOD.
Ultimately the choice is yours. The festival runs the entire month and I suspect many city treasuries are well funded to continue to host the festival for the duration.
The Artisan Festival does not work this way. If everyone turned in a single low point value BOD equal in value to the elf and someone else came along and turned in several BODs worth more points, assuming the lowest percentage of participants were awarded, "the jerk" would have the most chance of receiving a reward, since s/he can only receive one reward, the rest of the participants would have an equal chance to receive one of the rewards until the total number of rewards granted equaled to whatever was dictated by the growth state of the tree.