I see what you mean, but I’m not sure how it could be improved.
For me personally, just saying “prepare for a much longer lockdown” wouldn’t be better; without a concrete number it makes much less of an impact.
With a concrete number in there, even if it’s very clearly just a guesstimate with huge error bars, it makes you think about what the effects might be in the real world, which I think is helpful (in fact it’s the very point of the whole post).
For me personally, just saying “prepare for a much longer lockdown” wouldn’t be better; without a concrete number it makes much less of an impact.
With a concrete number in there, even if it’s very clearly just a guesstimate with huge error bars, it makes you think about what the effects might be in the real world, which I think is helpful (in fact it’s the very point of the whole post).