No, I can’t “prove” to you that a “beneficial” institution would not survive

I don't believe I asked you to prove it. I asked for examples of such institutions. When you say "institutions", the first thing that springs to my mind are corporate landlords taking investor dollars to buy up residential properties, and artificially inflate housing prices. That is an example of an "institution" that is contributing to the problem. That institution exists primarily to benefit the interests of corporate entities and ultra-high net worth individuals. That is an institution that should not survive in its current form.

Either way, it’d miss the point that there are in fact institutions that do good in the world that are built on the current systems and need some means of transitioning or surviving your radical change.

Name some. You're assuming I'm either going to destroy such institutions, or that I will need some sort of "exception" in order for them to continue operating. I don't think this is likely. I think that such institutions would fall well within this plan. I think they could, for example, structure their portfolios to pass the security tax obligation through to the natural-person shareholders who own and control them.

For example, that abusive REIT I mentioned above is currently under the control of Problem Class shareholders. That problem class is using that control to transfer wealth from the working class to the problem class. When the Problem Class shareholders withdraw, this REIT comes under the control of Working-Class Shareholders; the kind of people who are harmed by that exploitative behavior.

Do you know how you make progress? You gain a deep understanding of how things work

Which is why I'm asking for examples. What harm do you think is going to arise from driving the Problem Class out of these nebulous "institutions"?