Why exactly?
Numbers in the majority of Europe are looking the same. Wether it has been a hard lockdown, partial lockdown or even no lockdown at all (but with social distancing)...the new infections and death tolls are rapidly declining almost everywhere.
Sure, every country will claim victory because of their own version of the lockdown, but I remain skeptic...
Here in the Netherlands it is looking more and more like the first basic measures (no big events, no handshakes, social distancing and working from home) had the biggest effect.