Same here. I was looking all over the site for "the idea" or the differentiator ... couldn't find it.

I think most of the approaches you mentioned wouldn't hold up for a large stock exchange because some off-platform trading site would spring up to fill the gaps. For example, you have a minimum holding period, but off-platform you can "sell" your shares at the current market price, then transfer them for free once the holding period ends. Or something.

I think you have to change the way the shares themselves work somehow (or how dividends work, etc). I'm not sure, seems like a hard problem.