Prices are To hight (in relative terms)

[DracotheDragon]

snip

dialogue from the Hitting the Cactpot quest

If all your numbers match, then ding, ding, ding─you've hit the Cactpot! You'll receive an embarrassingly large number of MGP, and an extravagant prize besides!
And with the Jumbo Cactpot, the more participants there are, the grander the prizes become. Just imagine how many MGP you'll stand to win if all your friends and allies join in the fun!
When the time comes to draw the winning number, look no further than the lovely Cactpot cashier. She will provide you with everything from first prize to consolation points.

additional

In addition to your other winnings, you will receive the Early Bird Bonus if you claim your prize within one hour (Earth time) of the Jumbo Cactpot drawing.

(we do not know what this bonus for being the first within the hour of the draw.)

bolded the parts that can be taken as first come first rewarded. The idea of a first place prize loses its meaning when multiple people strike the same part, a tie in the chocobo races has both players in 1st gain the same experience and MGP as the 2nd place, meaning in truth there is no first person.
thus the same could be said that they will follow the FFXI approch and split the winnings, with each and every winner, not only this but in ffxi if someone claimed the pot and the other person was not on the rest of the time limit ( i think it was only a 2 hour collection time from the first person) then they lose out while the first person gains the remaining pot.

not stating the odds are not good 1 out of 10.000 is really good for a game with 4 million active users, but it is how they handle this that is worrysome,

also i do like the full refund if you lose, that is kind of SE,
again i aint arugeing the jumbo cackpot is a impossible chance, it is just a variable that is very anomalus and it is more likely to be lost then gained.the original wall of math was made ignoring this mostly due to the small chance of winning, compared to how they hand out the prizes.

[Niwashi]

bolded the parts that can be taken as first come first rewarded. The idea of a first place prize loses its meaning when multiple people strike the same part

If you think that just the fact of naming it "first prize" means there's only one, then the same would hold true of "second prize", "third prize", and "fourth prize". Yet the game explicitly describes the conditions for each one, and those conditions don't involve the luck of other players. There may or may not be multiple players who get all four numbers right, but there's certain to be lots who get just the last number right. Do you think that that fourth prize gets divided between all of them? Or that only one of them gets anything?

a tie in the chocobo races has both players in 1st gain the same experience and MGP as the 2nd place, meaning in truth there is no first person.

The chocobo race is different, because it is a race. That's the nature of races, that your result is measured in terms of how you place among the other contestants. So that has the concept of a tie, and therefore SE has to come up with a way of scoring ties.

In jumbo cactpot, the score is how many of the four numbers you get right. Other contestants don't affect your score because other contestants don't affect how many of the four numbers you get right.