But surely when that lockdown comes it's going to last for longer, than if you had acted earlier? The rate of infection is a lot higher than the rate of recovery (look at China, they're still weeks and weeks away from getting their total active cases down below 1000 - I.e. the stage we're at).
The ramp up should've started earlier, but as it didn't it needs to be accelerating right now.
In general I would imagine it's all very context dependent? The UK spokesperson today said their implementation of measures was based on data modelling of how best to push back the peak of the virus. Given that different countries would presumably be using different models and different data, you'd probably expect different timings in terms of implementing measures?
For example, let's say we accept that the coronavirus is going to be around regardless of what we do for X months and at some point every country will have to implement the harshest measures. One would imagine the optimal time for implementing the harshest measures within that time frame would vary from country to country depending on the circumstances. So a country like Ireland (with a younger population, more rural and relatively few community transmissions) would probably benefit more from a later implementation of those measures than a different country (say where there's a older, urban population with a higher degree of early community transmissions). It wouldn't make sense for me for them all to take the same "go heavy as soon as possible" approach when the pattern and timing of the illness could vary to such a degree.
Maybe they're also taking into account other factors, like trying to time the peak of the virus within the country for a time when they think there will be lower strain on the healthcare service from other illnesses? Or (if they really do believe that the virus may lull in the summer months) trying to time it so that the harshest measures end as the peak subsides?
I really have zero clue and am just speculating but intuitively it makes sense to me that it would be more complicated than
just going hard and early.