Technically they could prevent the early leaks by getting rid of the physical magazines entirely and switching to digital-distribution-only. Which they're not gonna do any time soon, obviously. If that happened, then they would totally control the exact moment it was available to anyone. So in that way they could not give Manga Editors enough time to scanlate. Course, then you would end up with a Horriblesubs type of scenario where they got ripped and put up for free immediately.Stop early Edited Manga is nearly impossible because it would have to change the way the publishers there in Japan distribute their magazines. The magazine must arrive in the stores before its release date, there is no way to change that. That said and given the fact that they want to shut down sites that were based in countries they don't any power... It tends to be a failure again.
Improve their services around the world would be better than try to stop Edited Mangas. USA is almost a heaven for me, here we don't have 1/4 of releases USA has and no ways to read it digitally besides Crunchyroll, which is in English and narrow the amount of people who can use it.
It is not just a problem in USA, it is a worldwide problem that they are dealing wrongly.
As an example, thepiratebay was aimed by the entire entertainment industry more than once and it is still alive. Only one site, even more a bunch of them.
Tonari no Young Jump works in a pretty good way, I think. I'm glad One Punch Man is doing well, because it's setting a precedent that that business model can work. The series goes online on their official reader (Even though it's kinda slow) and is free to view by anyone from any region. So I always just read that series on their site. Course, the official English version comes out later and you have to pay for it. So it's not a flawless system.