So I was playing a ranked game and randomly two teammates decide they have had enough and leave the game entirely even though we were in a really good spot. Anyway, the game goes on for another 15 minutes and ofcourse, the enemy team stomps us 5v3. How in the hell is it fair to lose MMR that game? Okay sure, let the enemy team gain MMR normally, but why in the hell should my rating suffer because of two knuckleheads that made the game literally impossible to win.
Doing this leads to huge MMR inflation across the board because the system is now unbalanced. You also open up the option for boosters to play in groups and if it looks like they’re going to lose they just have a sacrificial account abandon.
It always sucks in the short term when this happens, but in the long run it balances out with an equal number of free wins and not doing it makes things worse overall.
If someone leaves after fb and that team wins. It creates imbalance aswell. So 6 people lose mmr and 4 people gain mmr. So the deflation factor is there.
But no inflation factor. Also if people just leave and u lose mmr thats not a correct way to calibrate ur skill
It’s more about scale of the imbalance, since as you notedd there are already factors like 4v5 teams winning or players being capped to 1 MMR on the lower end that impact the economics of MMR.
The big differences are that most of those scenarios only have like 1/10th the impact (for example 1 player vs 4 then figure like a 60/40 uphill win) a flat “you have a leaver you don’t lose MMR” policy would, and that they aren’t easily abusable in the same fashion.
I doubt this is whats stopping boosters from going rampant. Boosters already exist in Dota and the only thing currently in the game to stop them is the measly “Smurfing” report option which from experience never worked even in cases of obvious smurfing.