I get the frustration everyone's feeling. We want to know the answers. The models are missing key data so they can't tell us much. They give scenarios and then the media headline writers pick the most extreme case and make it sound like a prediction. It's not a prediction, it's a what if - a particular set of assumptions is true.
The models currently show as worse case, what if the current R rate is maintained (it won't be), our current knowledge about the protective effects of the vaccine/booster and protection via past infection are true (they won't be) and it's about as dangerous as Delta (we don't think it is) what happens? The answer is a disaster.
It's also only one of the calculations in the model. It's not the one they think is the likeliest, it's not the optimistic, it's not even the one they describe as "reasonable worst case". It's the scary one, that headline writers lock onto, and that scares some people and makes other people laugh.
If the more extreme predictions are accurate we'll know from London next week, and from the whole country on/before New Year.
If the optimistic predictions are accurate, we'll have a bad month in January, but there will be little point in trying to stop it rolling through. If the pessimistic ones are accurate we'll be slamming the brakes on hard and trying to make the hospitalisations/deaths spread out over 3 months, rather than 3 weeks.