Why can't you make the max payout based on a percentage of the total money spent on the case by the loser. That way if company A spends $10 million on the case

Why can't you make the max payout based on a percentage of the total money spent on the case by the loser. That way if company A spends $10 million on the case and loses, the winner can recoup say $8 million. But if Person A spends $50k on a case and loses, the winner can only recoup $40k.