Interesting idea, I believe that downvote should not serve to erase someone's profile, with the exception of constant plagiarists, so I believe that it should not be used by default.
But as they said here, there are posts with bad content that gain a lot of votes, sometimes constantly, and always from the same curators, and this in the long run can make it seem like only one side is benefiting, and as we've seen, that it always generates conflicts. Unfortunately, many people don't think about the long term or the effects of their actions and continue to do what they want.
Some people decide to stay on certain projects more for profit, and the really good ones who aren't worried about the financial part walk away, and then we see many projects not reaching the potential they could.
I believe that this scenario will hardly change, and then it's up to each one to choose what is best for them...