I got into MFD back in 2012, a pre-owned Linhof Techno with Schneider Digitar lenses with a pre-owned Aptus 75 back. Today I have the same system, but the back is now a H4D-50 and I have a bunch of additional Digitars.
The situation has changed though, Copal shutters are discontinued, the only reasonable replacement seems to be focal plane shutters, Schneider Digitar lenses have been discontinued, and with those the symmetric small aperture distortion-free low-complexity low weight designs are, well, history. CMOS backs are here, but they even have issues with weak retrofocus lenses, and you see the dealers and manufacturers push for solutions like focus stacking, keystone correction, cropping rather than shooting with traditional "large format" techniques.
I think cameras will converge, the time when the digital back was a drop-in replacement for a film back is fading away, and we'll see cameras become more and more electronic and similar and in the end only size will differ. Do you want a big Sony Mirrorless or a smaller one? For most people this is an excellent development.
However, when the workflow will be essentially the same like a consumer camera and the image quality of the consumer camera matches or exceeds what even 4x5" film could do, then I don't see much of a reason to go even bigger. I do agree that MFD is really super-great concerning image quality, but I don't buy into is that 135 is super-bad and that your work would be second rate if you use it. The difference is there, it's just not that meaningful any longer. It's no longer the days when P45 was the king when you compared a 16 megapixel Canon 1DsII with the old TS-E24 with a 39 megapixel P45 with an SK35. The newer lenses and the A7r, D810, 5Ds etc has made a difference, the quality is at levels now that before was only possible with medium format digital or large format film. I won't pretend that it hasn't happened.
As 135 format has progressed with better and better image quality (and I have become better and better at controlling color from any camera) the attraction of MFD has for me become less about image quality specifics, and more about the traditional shooting experience and elegant design tradeoffs that you find in the truly purpose-made Schneider Digitars. My "passion" in medium format is not about digital backs, it's about field view cameras and large-format-style lenses. The MFD industry has however done their best to do away with the uniqueness and focused on one thing only: become more like the user-friendly and generic 135 cameras just with more megapixels. And, they're probably doing the right thing... they can't afford to satisfy niche interests which I'm aware mine is.