Basically bankers make money when money flows. It flows only when "there is something better". So to keep making money there always has to be "something better" and ultimately that becomes unsustainable.
1929 was a re-adjustment, where all the bullshit is cleaned away. It was perhaps the first time it impacted such a large portion of society. An education of the masses if you will. Crashes did, and will, keep happening again - as long as the myth of "forever going up" persists.
In the early 2000s it was property. Today its (maybe /likely /probably) crypto.
At least today society is notably, collectively, smarter. There are a lot more naysayers in general, and whole there will be crashes, they tend to be more limited in scope and reach.
But greed, the root of all of this, will always be with us. Greed offers some to be winners, but most to be losers.