The two are not mutually exclusive. They can (and should) button up the launch OS and then continue work on the revisions to be distributed online. We're all familiar with this model from our smartphones and PCs. This is why version numbers exist.
To not have one version of the OS that is complete when shipping dates are passing is... not a practice I would recommend.
I'm not arguing that it doesn't work, I'm arguing that it isn't shippable.
In other words, what is in the remaining 10% (OS) and 20% (back end) that needs to be done? You and I are asking the same question.
If he could answer it in a manner that adequately explained the items missing, yes I would. And by "adequately", I would need a fairly technical description listing the items that needed to be delivered, and why they haven't been completed before now. On that point, I remind you that I've already said that software dev and backend infrastructure should be easy to plan within the framework of a pandemic.
So yes, I would believe him, but it would have to be a substantial answer, and not the kid of thing that's likely to fit into a tweet or YouTube video.
Whenever possible, I try to take the Amico team at their word. Speculation is not helpful. I'm looking at what the Amico team has said, and what they have done. Sometimes the two do not mesh. When the two don't mesh, I think it's fair to seek clarification.