Nobody would have prevented them from changing the ToS after a few years to not refund new purchases after date X. It would have been a bad signal but if the platform was successful people wouldn't really mind.
If you put it in from the start it wouldn't be an issue. Or even just guarantee refunds from purchases in the past 3 years. So there is a rolling window and you can lessen the impact but closing the store and continuing operating the platform for 1-2 years.
