And you cannot buy a new GM5 camera body (for example) if there are none made - so we just keep using what we have as there is no real replacement alternative.
The G9 has been around for a while - I doubt if G9 owners are presently about to give up on these excellent camera bodies.
Etc.
Re folks flocking to FF because they are being convinced that it's the bee's knees. I am sure there is a slice of the public for whom having camera model X is a matter of principle. Like driving a certain car.
I am no professional, I suppose I wouldn't even qualify as an enthusiast; enthusiasts, as I see it, are much better at photographing that I am or will ever be or even care to be.
I'm out photographing almost every day, but picture-taking is not an end to itself for me. I am physically unable to discern some of the minuscule differences in... whatever... that members here can go on about for days. I am fascinated and read those threads, yet often I don't get some of the critiques. It's like discussing about the gender of angels. Post-processing is a tool when I need it -- I don't get a kick out of it. Most often tweaking shadows will do for me.
For me, photography helps me identify insects, plants, etc. That's much more exciting and useful for me (it all started when I realized that some of the plants growing on my property are poisonous for my animals, and I needed to be able to identify them so I could fence them out). Now, taking a neat picture of a life form is a great satisfaction, and I enjoy getting better at it, but without at least trying to identify that life form down to species is only half of the fun. For other 'non-enthusiasts' it's all about recording their kids' antics and them growing up, and/or producing memorabilia during holidays.
What I am trying to get across: DPREVIEW habitues are not 'normal people'. It is not 'normal' for the average person to have more than one camera.
MFT is ideal for 'normal people' who like to take pictures, for whom a point-and-shoot doesn't cut it, who like to have a degree of control over what they are doing, and if need be they can always use the AUTO mode when they're not in the mood for thinking. For people who feel that a smartphone can't do it all, especially if they aren't into buying a new smartphone with yet another additional camera every 18 months. For people who are unwilling/unable to invest in steep learning curves or huge amounts of money into gear and are even less likely to take huge camera trolleys on trips. For people who shoot handheld and can't be bothered with tripods.
I am sure there are many more MFT owners out there than we can infer from the data in this forum.