Recession happen because greed becomes the normal state of affairs, no matter how dangerous that normal is. See, finance people are collectively in charge of enough wealth to drive the whole world under if they get it wrong, but never have to deal with the full consequences of what they wreak.
We can’t stop them from happening because the ruling class, the people that never suffer any consequences when the economy fails, benefit by the normalized greed.
Greed can’t get normalized in a society unless it helps some people lower on the totem pole and it goes down hill from there. So ultimately the public interest is served. The recession that happened at the tail end of the nineties, what they called the dot com bust, happened to give us the Internet, and that survived the downturn.
So the boom bust cycle is ultimately good for society despite the greed and loss. But it really sucks if you are unaware and don’t prepare for these.