I mean JUMP (and other magazines) coul realistically try to make a Netflix like subscription model or something (first starting in Japan), imagine paying 1,000 Yen a month and you get I don't know all of Shueisha's magazines online before the physical street day or something like that. Or maybe 500 yen a month to get digital WSJ some days before street date.
It's not like these leaks happen only outside of Japan, people in Japan also read leaks/chapters before street date, right?
If someone is gonna pirate they are gonna pirate, but there is people that will support the official release.
Put another way, there's also people in Japan that read scans of for example, One Piece and that doesn't mean there is also lots of people that will buy the print magazine.
Heck, it's not like JUMP the print magazine has value, like sure they can get expensive over time particularly when a new series gets popular, but most people just dipose of them.
I know I would certainly pay... maybe not $10 a month (because obviously mangaplus won't be offering every manga from every manga publication Shueisha offers in Japan but a "select few titles") to get official chapter early (say on Friday, and thus eliminating the "need" of scanlated chapters).
But I think maybe paying $5 a month or say a $25 yearly subscription (Outside of Japan) to get chapters on Friday (AKA digital first) would be a smart move, would obliterate the need (and in fact the very existance of ) scanlated WSJ manga since the official release would be pretty much at the same point of the unofficial ones.
Edit: also it would be naive to think this would eliminate piracy all together BUT i think it would diminish it, or at least eliminate the most important factor which is people who read it ahead of time. Like seriously, how many views do you think are from people who read a manga the first hour it releases? The vast majority I would think (Probably 80%, which is what Shueisha is losing to manga piracy )