You don't have to have the largest multiplier to win, you just have to be the most recent.
Seems you bring unique terms of contest at this time and somehow I feel this is unfair for someone that hit the highest multiplier in the early days

Yeah I know this competition isn't about who has the highest multiplier but the most recent that hit the required multiplier (50x or more), I think most people will prefer to join this competition in the last days of it although as you said before there is no guarantee to hit it.