I did this, 2013-2019ish. Unfortunately there has been so little development in m4/3 sensors over this time period that my iPhone has replaced it for all scenarios except occasional extreme-tele. The improvement in quality offered by even the best m43 camera and glass over the latest phones just isn't worth the effort to me anymore at focal lengths below 200mm-ish, or I want to do something that requires a traditional camera "hot shoe" like external lighting.

The latest and greatest m4/3 camera today doesn't really take still pictures any better than an Olympus EM-5 from 2013 (the increase from 16 to 20mp makes little "real world" difference), cellphones improved _enormously_ over the same period. With a modern iPhone, I get an extreme wide angle, "standard" and reasonable portrait focal length lens all in one device, with the files in Lightroom immediately after taking them. Yes you can argue for days about "fokeh" vs the real thing, but m4/3 isn't the platform you want to be on if rich bokeh was your primary objective in the first place. I've also yet to find a three lens kit that covers the range of a modern iPhone I can fit in my jeans pocket too, even in m4/3!

I think in some cases, many people just like the "ritual" of using an interchangeable lens camera as much as they practically get any better images than with a decent phone, which is fine! For some reason it's not fashionable in photograhy circles to admit this, I guess the fear of looking like a dilettante etc.

The 20mp 4/3 sensors have noticeable advantages in dynamic range and high-ISO noise compared to the 16mp sensors. It's not just more pixels. A new ~23mp sensor with further performance improvements should show up this year in the Panasonic GH6 and an unnamed camera from the company formerly known as Olympus, though it's not clear if or when it will make it to more pocket-friendly models.

Perhaps, but I have a Panasonic G9 (20mp) and a EM1 Mk1 (16mp from 2013) the differences, while measurable to some degree in benchmarks, in day to use are really not that noticeable at all. The m4/3 industry relies effectively just on Sony now for sensors as Olympus/Panasonic do not make them, and there is not that much commercial incentive for Sony to invest more - this is why we only get a sensor feature bump when the Sony sensor catalog finally gets a new installment in 17x13mm.

I noticed a big difference going from a Panasonic G7 to a GX9. It gave me a stop more usable ISO and a lot more ability to bring up the shadows when editing.