I've noticed this sentiment expressed time and time again on this subreddit, so I want to run through why Riot will never implement a system where the team with a leaver doesn't lose rank or loses less rank than normal.

I get it, it's frustrating. You're playing a ranked game and suddenly you see the dreaded disconnect. Now you're stuck playing a 4v5 and almost certainly taking a big rank hit, through no fault of your own. It seems like the only fair thing would be for the person who left to take the loss, and the rest of the team to just get a wash, or at least have the rank system take into consideration that they were playing a 4v5.

But take a step back and consider what such a system incentivizes. In any ranked game, the players on the losing team will benefit if they can get someone else on their team to dc. Imagine what a game with 5 solo queueing teammates would look like if they were losing, in a situation where their choice is either take the loss, or somehow get someone on their team to leave.

Every game will devolve into some argument about who's to blame for the loss and should dc. After all, if they're responsible, wouldn't it make sense they lose rank and their team walk away unpunished? Players will start deliberately trolling their teammates, trying to make the game as unplayable as possible so they just give up and dc. We'd be entering a system where this behavior would be rewarded. "Oh-uh, we're losing. Better bully/troll/trick one of these other guys on my team to dc so that I don't lose any rank."

There's a reason why there's no major competitive video game that has a system where you take a smaller loss penalty (or none at all) because your team has a leaver. It would be a disaster and quickly make the community one of the most toxic in online gaming.