The only series where they haven't gone with the chapters coming out that week were Blue Exorcist and Seraph of the End. Both had a short enough gap between what had already been published and the latest chapter to bridge the gap quickly (Seraph is well on its way on a 2 a month release schedule, blue exorcist caught up in a matter of weeks). You can't pull that with something as long as Kingdom. Or indeed any weekly series that hits a certain length. It isn't feasible.
And they wouldn't handle it differently with physical copies? No shit, because those are volume releases, you're comparing what's possible with a 200 page a volume bimonthly release with what would be 20 pages a week. What's more if they want to catch up in volumes, either digitally or physically, that works. You release more product at its standard price, it's still available individually. They achieved this with Naruto and One Piece successfully, mostly by making sure that all the volumes released stayed in print, allowing readers to get them when they can. Now say you want to catch-up in weekly releases. First off, we're talking quantity of workload. You'dd have staff translating, twice, three times, maybe even four times the amount of material on a weekly basis to try and go from chapter 1 up to the present chapter. Inefficient and costly. Put that aside and you have size of release. Digital doesn't have a real size limit to it, but that extra 40/60/80/et cetera pages of a catch-up title being released every week would ramp up the cost of the anthology to meet the costs involved. You leave it behind forever and Jump loses a core part of its day and date marketing by just... being the old, awful US Jump that ran into the ground. being an english alternative to the weekly/monthly publishing schedules is the whole dang deal.
Tl;dr: Releasing long-form series from years behind the JP release in weekly issues doesn't work at all for int'l jump.
