And if you divide the player population in 4 equal pieces, you're not taking into consideration how active players are.
I can imagine people with less then 50k score are much less active or maybe don't even log on anymore. This would mean the gold and platinum levels get crowded even more.
uhm, no. I was actually considering that higher score players are more active.
I'll give you some numbers, these are the players that logged on in the last 48 hours, arranged by score.
Platinum (score >= 89500): 479 players
Gold (score<89500 and >= 19050): 2290 players
Silver (score<19050 and >= 4160): 3069 players
Bronze (score<4160): 7998 players
If I increase the platinum limit to 100k or more there would be no competition for the platinum top500, you just submit your deck once and you are good for weeks.