It would be foolish to predict the thing that already happened!
Predictions are hard, especially about the future, but they aren’t that hard.
It seems pretty clear from context to me that Topol is saying that the thing that already happened is that someone predicted that Omicron would serve as an exit ramp, not that Omicron has already served as an exit ramp, i.e. The Lancet article that he linked to is predicting the end of the acute phase of the pandemic due to Omicron, and the existence of that article is what already happened, not that the thing it's predicting "already happened"
It seems pretty clear from context to me that Topol is saying that the thing that already happened is that someone predicted that Omicron would serve as an exit ramp, not that Omicron has already served as an exit ramp, i.e. The Lancet article that he linked to is predicting the end of the acute phase of the pandemic due to Omicron, and the existence of that article is what already happened, not that the thing it's predicting "already happened"