The cost of any realistic monorail replacement would surely be prohibitive. Whatever form it took, it would be the biggest investment in the history of the park for zero commercial benefit. The question then becomes how long can they justify keeping the current system running vaguely reliably? As it is, I very rarely use it as the capacity is now so poor, even when running 5 trains, that the queue is usually so long that it just isn't worth it. At a guess, I'd say that each train now makes at least 1 less round-trip per hour since they stopped letting people wait in the loading bays, a capacity loss of around 500 people/hour.
