In software shifting left often also means putting more tasks into the hands of the person with the most context, aka, moving deployment from ops to developers.
The main benefits you get from this is reduced context switching, increased information retention, increased ownership.
But it has to go with tooling, and process that enables that. If you have a really long deployment process where devs can get distracted then they will lose context switching between tasks. If you make every Dev a one man army that has to do everything on their own you won't be able to ship anything and your infra will be a disjointed mess.
They key thing is reducing toil, and increasing decision making power within a single team/person.
From the sound of the article they might be just squishing two teams together? What's the advancement that made the two steps be able to happen at the same time?