Older anti-psychotics work very well for acutely and floridly psychotic people. Modern anti-psychotics seem to be objectively very poor in my opinion at treating acute psychosis. This could be due to the mechanisms of action.
If the process of psychosis involves the flooding of the brain with Dopamine, perhaps the excess Dopamine is being picked up by Dopamine receptors from dormant neighbouring, neuron dopamine receptors. The old fashioned anti-psychotics block re-uptake, therefore preventing the Dopamine from entering dormant neurons. Modern antipsychotics block the Dopamine to slow the flow of Dopamine into the synapse. If there is already a flooded overload of Dopamine, then there is little immediate benefit to be had from Modern Antipsychotics.
Modern anti psychotics probably have a better chance of achieving results in prodromal or mild/emerging psychosis or as a preventative measure in a schizophrenic who is experiencing a remission of symptoms.
Another take is that newer antipsychotics are just not sedating enough and so they don’t increase sleep or REM sleep. Modern antipsychotics aren’t as sedating.