I mean, Kuo has a better track record than me, so I do encourage believing him over me, but here's my take:
Micro-LED still isn't ready for the kind of scale of deployment the iPad would require. Maybe October, sure, but I think Apple would want to refresh the Pro in March honestly. Perhaps two refresh in one year but that also seems low-probability to me.
Why a current owner should upgrade; Well, if you have the latest pro right now, you shouldn't. Same way you probably shouldn't upgrade from Apple Watch Series 4 to 5 or every single time a new Mac comes out. An upgrade for a product segment that has reached relative stability isn't about enticing people already on the latest platform to go to the brand new one. Some will, sure, but it's more often about giving extra reason for people with 2 or 3 generation old hardware to jump to the newer one.