What difference does it make. Everyone had 3 months heads up - the world saw footage of children laid in body bags, 24/7 crematoriums, people locked into their homes, people dropping dead on the streets. What didn't we know? Would 3.5 months have made a difference. The WHO didn't declare a pandemic until it was everywhere. This is a global problem.
But that's what a pandemic is (up until them, it was either endemic or epidemic). They can't change the meanings of those words just because.
Yes, we knew quite some time ago. I knew, because I read science news daily and because it's within my broader field of study. I was worried. We didn't know what the death rates would be - or even that it was going to be all old people (such a relief, really - compared to when it seemed possible that infants and babies and toddlers might be equally susceptible).
Each of us reacted differently and most of our institutions reacted not at all. "The world" doesn't watch all this news, there are still tons of people who have no clue this is happening, even right here in California. It's we who want be helpers or leaders who must still try to do something to mitigate this disaster.
Yes, 3,5 months would have made a huge difference. In one month, I think California and other well-funded, well-informed states will be getting a grasp on this - but no one knows if we are capable of stopping it before we become Italy. The methods we use to keep the death rate lower, here in the US, need study and it's worrying that we didn't plan for data gathering.
It is a global problem, but it is one that divides by its nature, as we all need to eliminate pathways for the virus by...less contact.
And it's okay to take a different attitude. Some of us want to fix things and feel compulsive about it, others want to chill and go on with life as before. That's the way it is.