Yeah, I don’t see how a rate that high will allow even a rich person to make this work. Unless you die very quickly after taking the loan, paying 8% for a few years will be more costly than just paying LTCG and selling the stock. And it gets worse every year.
But even if we cut the rate down to 3 percent, you are still going to be behind if you carry the loan for a long enough period of time (unless, of course, the stock keeps appreciating). I can’t imagine that these strategies rely on stock appreciation as that is not really a given. But maybe they do, it’s not a terrible assumption if the time horizon is long enough.