All has gone quiet on the MF front. Since the 2018 release of the 150mp sensor and IQ4 camera, it seems like the resolution war is over.
Trying to think back, with the flagship cameras and the sensor releases, it's kind of amazing. The 80mp CCD did what, 5 years as king before the 100mp CMOS came out in 2016. Then the 150mp CMOS in 2018.
Shy of the 120mp 33x44 used in the Phase Industrial cameras, there isn't the upgrade cycle that we had come to expect. What's sick is that we're looking at a video camera at 140mp in the Blackmagic URSA Cine, capturing at 60 fps.
I can see where selling a 'new' sensor at the same resolution isn't going to get folks to upgrade, even if it was a few stops better with light. Even in the FF world, it seems like 8k is the target resolution & it's about auto-focus or frame rate.
Have we made it to the end?
It may depend on what you mean by "replacement". If you mean by "replacement", that the previous sensor was then discontinued, yes, then maybe the 150mp sensor in the IQ4 (released September 2018) has had one of the longest runs. But if you don't qualify it with
and discontinued, then the 50mp sensor that has been used in Phase One IQ1/2/3 50, and Fuji GFX 50R/50S/50S II, and Hasselblad X1D/X1D II/907x CFV 50c (and CFV units before then), has had a longer run, we're at 12 + years.
Far as practical resolution requirements/limits is concerned, in the consumer space, we're getting there. There will be another model from Phase One at higher resolution. Maybe later this year. Maybe next. Considering that the IQ4 150 was the flagship product for 7 years, if an IQ5 250 comes out this year or next, then we're projecting into what, 2032 or so before any possibility of another model being released (IF).
And at that point, what will life even be like on the planet Earth?

At 150mp on up, it gets very niche, think industrial/reproductive applications and super high end specific creative endeavors. I do have numerous non-industrial clients who have already told me to put them on the list for the IQ5 whatever, whenever it comes.
So - yes, I think for Phase One, for almost all camera manufacturers, resolution limitations are close to being conquered, when it comes to mainstream consumer applications. For Phase One/Medium Format, their defining strength has always been premium resolution and premium image quality. So for them, industrial applications are an obvious dominant market to continue to evolve in. For the 35mm world, they need high quality, but their future lies in pushing the boundaries of the various ways they can capture creative images effectively.
Steve Hendrix/CI