> If real money becomes a "hot potato" how does that encourage long-term investment?

Because, for example, building a business that achieves steady positive cash flow would be better than a short-term one-off opportunity, since that one-off would only delay the issue of demurrage.

> And if the wealthy transfer their stagnant wealth to something other than currency, like gold or real estate, their dollar value will skyrocket over time as the value of the dollar plummets.

There's nothing in that argument unique to a demurrage currency. That same is true for inflationary currencies like the dollar. You've taken a rather extreme case of a bank-run, which is disastrous no matter the circumstances, but doesn't prove anything.