Losing a winnable game due to surrender feels horrible. Why push towards more of this?
I've been through way to many games where people want to surrender because they only see that THEY THEMSELVES or the team as a whole are a few kills behind. Noone is carrying, lets pack it in.
Never mind that our 0/0 botlane is up 40 cs, we have better scaling, their carry is actually easy to get shutdown gold from once we group. We have a far superior team-fight once we get to that stage. We have more dragons/towers. No. Surrender and move on. Even in Ranked. That's absurd.
I get that maturity levels have gone down as the game became more popular. And I am not exactly playing in high diamond. But the thoughts going about the board of giving selfish and easily demotivated players more agency in giving up games is terrible.
Yes, you should surrender unwinnable games. Those are not fun to play out for either team. We had a lot of that at the start of the season.
But the criteria for unwinnable needs to keep more in mind than KDA and your feelings.