Jenna, it's all about the acceptance rate & your position in the sequence. No. 1 lands & the rest follow at whatever time spacing the acceptance rate specifies. If you're no. 23 you'll land 22x the spacing behind no. 1.
PRMs allow for an increased acceptance rate so the average spacing between landings will be less. You're still no. 23 but 22x the spacing is a shorter time.
Focus on the landing time. Whether the delay is achieved by a 20 mile downwind or a pattern it's still a delay. And you'll still land 22x the spacing behind no. 1. Understandably it feels worse because you're tracking away from the runway!
I'm not a SY TMA controller but I think jj232 answered your question: "maybe the guy next to you has not called visual so we still need you on the PRM approach as we could have to break you out if they stray into the NTZ".