The focused loot was exclusive mats and rare minions just as they are now. The mats were selling for 100s of thousands and the Bluebird and Nutkins went for multiple millions and this was at a time when 1 million gil was worth a lot more than currently.
They are still intended as a daily activity and not meant to stockpiled, the fact that players have found ways to stockpile rather than doing them isn't a reason to make them unlimited.My point is that what made sense back then may not be valid today.