To suggest that Canon is not changing strategy with the changing market conditions but that Sony and Nikon are is misleading. Clearly Canon has removed the EF-M line, discontinued most of the EF lenses and gone all in for R mount over a 5 year period.
After Magic Lantern showed what could actually be done on the 5Diii, the release of the R5 was quite revolutionary and similar to the 5Dii in that sense. Its capabilities redefined what a hybrid camera could do and surprised (annoyed) many.
To say that the industry is changing but not Canon because it hasn't allowed open access (or very limited licensed access) to 3rd party RF lenses is not looking at the bigger picture.
Apple is the market leader for phones in profit not volume. They aren't bleeding edge in many ways but they work together within their walled eco-system. Users accept that limitation for the benefits of compatibility and it has been a good strategy for them.
Canon has for the last 50 years been THE technology leader when it comes to cameras. It doesn't surprise me the smallest, that Canon managed to catch up to Sony et all in terms of sensor design / fab / AF / IBIS. While it surprised me that they skipped a generation between front side illuminated sensors and stacked sensors, it certainly didn't surprise me that Canon would do a stacked sensor eventually. Canon is now doing 90nm / 60nm fab, something if you talked to people would have been seen as nearly impossible 5 years ago.
From a technology perspective - of course, Canon has changed with the industry as well, and many times led the industry but this is, i suspect, a more cultural issue with Canon than a technology one.
And this is one area I would wish that Canon was a leader, not a follower.
Even if you assume that Canon is doing the right thing with respect to mount licensing (and I did list some valid points in favor of licensing) there's a lot that Canon is keeping pretty close to its chest and by the lack of people that want to talk about it in the third party arena, they are probably tucked behind NDA's as well.
As I mentioned, this was an area (third party) that Canon was unmatched in the EF space.
I was having yet another morning coffee (it's 11am!) and thinking about this a bit more. There's been a lot of "well if you don't like what Canon is doing .. then move". That's always the case, but how many would move right out of the industry altogether? the market leader does have an impact on the overall health of the market. Some food for thought.