Even if a cut isn't taken and there aren't other inefficiencies, any money tied up in long-term predictions is earning 0% instead of whatever the current risk-free rate of return is.
Assuming that the prediction market is perfectly priced right? How accurate is that assumption, or are you counting that as an “inefficiency”?
IBKR relentlessly advertises on the radio, so I’m aware that on their scheme you earn an interest like incentive coupon for every day you hold open the position.
Earning less than the risk free rate is a 'cut being taken'.