Plagiarism in short is a crime on Steemit. Flagging is the deserved punishment for Plaigarism, When you are abusing a system you are committing a crime, it's no different to committing something life theft and selling it on the black market for a high price.

Steemit is quite small now, so many companies don't know about it but if it gains huge popularity over the years then they'll have to introduce a copyright system to protect other people's content. I am not a fan of the copyright system because it can be too strict sometimes, however it will reduce the number of plagiarised posts.