I'm going to suggest that "putting positive energy out", except for the possible (but I suspect largely overestimated) live crowd effect, makes no difference at all.
This is very relatable so I'm going to share some psychological background so you can all understand where I often come from.
As a child, I remember that my family or adults in general would often spread unfounded optimism about something. My grandma was the most guilty of it as I believe ignoring any worries and negative stuff was her coping mechanism (enough said that she died of cancer a few years ago because she refused to acknowledge she had any worrying symptoms until it was way too late to do anything, even though she knew she had ones).
As a child, you're taught that adults know better and you should trust them, but then you see their judgement was wrong and you feel cheated, especially if the outcome was much worse than what they were predicting and you ended up unprepared because of it. So I learned very early in my life not to trust something just because someone is saying it and to get sceptical about people focusing too much on the positive side but that's not limited to positivity only but any one-sided thinking in general. I would learn to take the opposite stance to test if the person's opinion is worth anything, if they can withstand my intelectual challenge with some arguments I'm unable to refute- if yes, then I get additional information, which is something I'm often guilty of (gathering too much information I don't necessarily have much use for just in case), if no, then I know there's no use to losing any sleep over the person's opinion because they don't seem to have any knowledge or judging capabilities that I lack, which is useful information too. It's my way of navigating the world that presents too much confusing information.
I also tend to be on the pessimistic side in my life because I've learned time and time again that optimism proven wrong is much more painful in my case than being prepared for the worst.