That's pretty much the only thing they can do.
I honestly thought that US Jump was dead when they decided to switch to digital only. When it was a magazine, it wasn't competing against scan websites. As a digital item, unless they were adding a ton of editorial content, it is in competition with scans, and if they were only publishing old content, it isn't even much of a fight. Transitioning to day and date with Japan in theory would give them an advantage, but we get english scans before Japan gets it- leading to things like creators wondering how people are tweeting at them about stuff that hasn't been published yet!
Viz cannot compete with scanners. Wednesday becomes a "avoid Mangaf" day for me, because all anyone talks about is stuff that US Jump can't publish for another 5 days. And what about series like HQ and Assassination Classroom that don't have early translations? They need to find a way to get all of that content out instantly. If next week comes, and the new series is Soma starting at chapter 42, that would be GREAT for us. However, for the vast majority of people who are just discovering Soma, they would be confused. They would need to google Soma, and probably read early stuff on scan websites. Driving people to scans is the LAST thing that Viz wants! And unless they were willing to give away at least the first volume free of charge to subscribers, they aren't going to be able to get away with just posting all the volumes for sale on day 1, because asking people to shell out money for more than a volume or 2 sight unseen is gross.
With World Trigger (and Cross Manage IIRC), they decided to start publishing a long term series from chapter 1 concurrently with Japan. And for the most part, it has successfully stayed ahead of translators. The site I read most of my stuff on doesn't even host english versions of World Trigger, and a few months ago, someone posted asking DTL and I where we were finding World Trigger so early! The main problem with this process is that you can't predict the JPN audience reactions (Cross Manage), and you need to start from Chapter 1- even a week late and your probably conceding to scanners. There are probably also publishing issues associated with this, but I won't pretend to know anything about how the Japanese side views the US side.
If Viz had unlimited manpower and money, EVERY SINGLE new series starting in Jump should be debuting in both publications day and date. Unfortunately, we don't live in Magical Christmasland, so we need to settle for whatever new series is starting when they have an open slot and staff. You are competing against scans otherwise, and scans have the advantage of being free. You aren't beating free.