Optimistic, yes. Blindly, no.
You're right there is some big differences between those countries but I think the commonality is that the worst is over for all three. More and more it's looking like herd immunity is the only way to stop this thing.
Italy lost control and had a big spike, essentially the worst case scenario with the health care system overwhelmed. Big ripping off of the band-aid that ironically has put them ahead in terms of recovery.
The infection and death rate basically mirror each other.
Brazil is in the middle at the moment but you can already see the deaths have started to dip despite rising infections, and I expect it to continue on that path. Brazil's average age is about 31 whereas Italy's is 45, and we already know this disproportionately affects people above 65. I think in Italy half of the people who died were around 80 with at least 3 underlying conditions.
USA past the crisis stage and won't have another big spike in deaths, certainly not proportional to the infection rate like we've seen before. They're probably the closest to what properly flattening of the curve would look like based on the data, mostly by default because of the different approaches by the states. Except New York which lost control for awhile but that was because of a policy decision that I won't get into in this post.
The latest up tick in infections started to really kick is in around 20 June (13 days ago) so I might be premature in my prediction but I don't think we'll see much in terms of deaths, maybe a small bump. You'll notice the deaths continued to decline despite infections flat lining during the period beginning of May to beginning of June.
I guess we'll know about a month from now.
Edit: the scientist I've been following during this pandemic is Mark Levitt. South African born Professor of Structural Biology at the Stanford School of Medicine, and winner of the 2013 Nobel Prize for Chemistry. A lot of what he said months ago seems to be on the money although this isn't his field. The more clever people looking at the data the better I reckon.
This article summarized what he has said before well. I haven't watched the video in the article though, I watched interviews with him elsewhere.
https://unherd.com/thepost/nobel-pr...-the-covid-19-epidemic-was-never-exponential/