Just a thought, which might explain the dealers reasons. How has the current economic situation and Covid, affected Hi fi retailers viability? I don't know the answer, but I suspect it isn't good. In theory, spending more time at home, you might look at an upgrade, but unemployment is rising, so buyers confidence is falling. If the retailer is doing his job, he should be doing some cleansing after a demo, which takes time and expense.
So I'm not supporting the charge for a demo, even in store, but maybe I understand it's part of a survival plan for the retailer