You seem to be confused about some relevant facts in your Canon time-line.

1, The FL lenses were / are fully compatible on FD-mount bodies. Did you actually drive off the road to success as far back as 1971?

2, The EF-S mount really doesn't rise to the level of a mount change. You're probably familiar with Nikon's DX lenses and cameras, similarly the EF-S mount is specific to cropped EOS bodies, a line of cameras that also can use every EF-mount lens ever.

3, The EF-M mount is very specific to a line of cropped mirrorless bodies. Both EF and EF-S lenses are fully compatible with these cameras via an EF-M adapter.

4, You've probably heard now about Nikon's mirrorless Z-mount? You mentioned it. That's the RF mount for Canon EOS full-frame mirrorless. What you probably don't know is that every EF lens ever is fully compatible with the RF cameras, via the Canon adapter. None of the EF / EF-S lenses are downgraded to manual. N O N E. None of the EF / EF-S lenses operate differently on different mirrorless cameras. None, nil, nada, zero, zilch. Maybe when you started this post to pat yourself on the back, you had a small nagging fear EOS technology has displaced Nikon as the upwardly compatible digital platform?

5, For all those EOS mirrorless options, now the age-old R, FL and FD lenses are ready to live on as manual focus lenses on digital mirrorless cameras with the appropriate adapter. So, if you'd gone with Canon way back when and stayed, all that Canon technology can be integrated onto a single digital mirrorless platform.

Falsely denigrating the global leader seems like an odd way to justify staying with the now #3 brand.

1. At the time, meaning when I made the decision, that wasn’t obvious. By your lights I probably did drive off the road to photographic success then.

2. You fail to point out that an EF-S lens won’t mount on an EF camera while a DX lens will mount on a F camera and work normally.

3. Wasn’t including non-Canon OEM adapters.

4. Every AF-S and AF-P Nikkor also works fine with the FTZ adapter. Nikon continued to make older lens types to serve its established market - specifically its older film cameras. Yes, I can still get new lenses for my F. That they won’t work with my Z fully is besides the point. And I don’t have to haul around an AF motor I can’t use with the F.

5. True but you need multiple non-Canon adapters.

Hardly degrading anyone. The leader is irrelevant to me. Nikon makes good equipment with a long history of not abandoning its user base. I went Nikon a long time ago and accumulated a large amount of glass some of it highly specialized (and not available in Canon mount). I kept using the F because it worked the way I want.

When I started looking at digital in 2006 I hesitated a long time because Canon was highly attractive. Eventually my wife decided that for once she could get me something she knew I’d like for my birthday. So she went to the camera store and bought me a D200 and gave it to me. So I wound up sticking with Nikon. I don’t regret it; equally so had I gone with Canon I don’t think I would have regretted it either. But I really do like the fact that all the D glass I have works great on the F. That fact kept me shooting film until this year.

I’m not a fanboy of any company. I neither like nor dislike either Nikon or Canon. They’re just tools - like this made by Milwaukee or Bosch - that enable me to create my art.

Now we just need that both, Canon and Nikon, allow 3rd party fully auto lens. It is BS to prevent us, the ones with that not so great budget, buying cheaper lens.