I agree the risks due to the near simultaneous end of transition and the virus could not have been foretold specifically in 2016. There was, of course, a more generalised concern about a pandemic, but obviously at a much lower probability.

On the other hand the presentation is dated June and it was the 13th of July that Gove formally announced the transition would end in January 2021. So this government consciously accepted all the risks that have been outlined. A risk is not a certainty, of course, but the increased risk is a deliberate choice.