Thanks for all the replies.
What I meant by "RFT surcharge" is that shops are charging a fee of about $10 a tire around here to mount or dismount run-flats - above the fees they charge to do those actions on non-runflats.
I appreciate the perspective about the value of purchasing wheels vs. frequent mount-dismounts. What I had thought to do in lieu of that was to change out once to all-season non-run flats then keep the run-flats in basement until I sell the car and give them to whoever buys it - or maybe try to sell the tires online. I understand the OEM run-flats get pretty poor mileage anyhow. So the twice-a-year mount and remount would not apply.