They're cheap! You can pretty easily get an olympus body for 2-300 bucks and a m43 lens also pretty cheap. The panasonic 25mm for example is usually around $100-150.
That all sounds big until you realize an a7 body is like minimum $1000.
They're definitely cheap, but so are the Panasonics, like the G7. What I'm saying is that I don't know what Olympus brings to the table given that they're more photo-forward, but not really much better than the Panasonic cameras, and much worse for video.
That 25mm Panasonic lens is a boss, though. I have two, along with the shorty 20mm Panasonic (which is not as good; it doesn't do AF-C, wtf?) and the 42.5mm Panasonic (which is the most delightful lens I own if I have enough room to use it).
I also have two of the Panasonic 14-140mm video lenses, and while I don't love shooting at like f3.5 they are invaluable when I'm working on-site.
What Olympus brought was in-body image stabilisation. Panasonics never had it (maybe they do now? I haven't been paying attention lately) and it makes all the difference if your thing is photography with just any lens that will fit.
That makes a lot of sense now that I think about it. The G7 and later have Panasonic's newest lens stabilization stuff with compatible lenses but you don't see IBIS until you go up to the S1 full-frame, which costs as much as everybody else's full-frame and the lens selection isn't great so you might as well go buy a Sony A7-of-some-flavor.
I run and gun with the G7 for photos, as it is my lightest camera by far, and I've been pretty pleased with its fast focus and in-hand shooting, but I could see how it could improve.
On a tripod. ;) Truth be told I bought it for HFR video, a bit better exposure/image quality so I don’t have to light myself in the face quite so hard, and because of the full-size HDMI port. The rest is gravy!
That all sounds big until you realize an a7 body is like minimum $1000.