So then what's even the point of resetting ranks monthly if you're most likely going to end up almost exactly where you were before the rank change? And allowing you to drop between 1-6 of a rank, but not dropping more than one level total. How much difference is there really in skill between a Platinum 6 and Diamond 1, but imagine the types of games the diamond 1 will get compared to Platinum 6.
The two reasons are suppossed to come from bungie days in Reach, first with reseting rank in theory you make players comeback to the game to get ranked again, before someone could get a 50 and never play again.
It also completly eliminated a market of players selling account ranked 50, players made money By selling gamertags sometimes even scaming players over it.