No, it has to do with the meaning of rating. You’ve played those rounds. You can’t just get the wins and not the losses when someone leaves, or else it’d be weak to exploitation and cause further inflation. It’d also cause the rating to fail its purpose, which is to figure out where people belong.
For example, right now when nobody gets any rating gains & losses when someone abandons, it’s completely preventing the rating system from doing what it needs to do. It’s also causing a massive problem in wasting people’s time. It’s also causing people to leave just to spite as well.
As for the dead weights, first of all the frequency of people leaving needs to be addressed in the design. But it can’t be dealt with too severely, or else it affects the innocent players too harshly too, such as those who gets a DC out of their control or their child cries out for their attention, and so on.
And the existence of dead weights can be dealt with in the design in different ways, but the most direct way to deal with it would be in the matchmaking itself. But if there’s no room to address with it in the matchmaking, then it can be mitigated in the way it rewards rating gains & losses. Which you can read about here: Suggestion to fix the rating system in shuffle